


Sodium

by 7PercentSolution



Series: Periodic Tales [15]
Category: Sherlock (TV)
Genre: Angst, Autistic Sherlock Holmes, Case Fic, Chemistry, Classical Music, Fitzroy Ford - Freeform, Gen, Implied/Referenced Drug Use, Kidlock, Non-Consensual Drug Use, OCD Mycroft, Past Drug Use, Protective Mycroft, SERIOUS chemistry, Sensory Processing Disorder, Violinist Sherlock
Language: English
Status: Completed
Published: 2017-05-27
Updated: 2017-05-27
Packaged: 2018-11-05 16:17:27
Rating: Teen And Up Audiences
Warnings: Graphic Depictions Of Violence
Chapters: 4
Words: 25,228
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/11017005
Author URL: https://archiveofourown.org/users/7PercentSolution/pseuds/7PercentSolution
Summary: Na 11 22.99Salt, an essential chemical for life and well-being, is ironically the combination of two of the most deadly chemicals known to man—sodium, an unstable metal that will burst into flame if exposed to air or water, and chlorine, one of the deadliest known gases. Yet this combination of chemicals produces sodium chloride, common table salt, which has been one of the most sought-after products in human history and is the only rock humans consume. Salt has more than 14,000 uses for mankind.





	1. Part One

"It was a mistake. I'm sorry, Sherlock. I should have realised that it would be rubbing salt into the wound."

Mycroft was standing in a bedroom of the South Eaton townhouse. It had been Sherlock's room whenever he was in residence, but it had never been claimed by him as "his". A subtle distinction, Mycroft was sure, but it just proved the point that Sherlock had never been at ease in the Holmes' London home.

The room was dark; only the light from a street lamp across the road came in through the drawn curtains. But, it was enough to show him his seventeen year old brother was crammed up against the headboard, his knees drawn up to his chest, his head tucked in so only the dark curls showed. He'd flung off his bow tie and kicked off the dress shoes, and shed the dinner jacket, which now lay in a heap on the floor.

Mycroft was similarly attired, but sartorially intact. The concert had been a black-tie event, with champagne and canapes, and a glittering audience to match. He had thought that Sherlock would like the Wigmore Hall recital by Sophie-Ann Mutter, a twenty three year old German violinist, who played her Dunn-Raven Stradivarius to perfection. It was supposed to have been a treat, and he'd kept the destination a secret until the car pulled up in front of the concert hall.

The first piece, Beethoven's Fifth Violin Sonata, in F Major, Opus 24, should have been twenty two minutes of musical bliss- and Mycroft had settled back in the box to enjoy Miss Mutter's playing, remembering the piece with particular fondness because it featured in one of the very few occasions – Christmas three years ago- when he'd been home long enough to play music with Sherlock. Sherlock had been asked to play the piece at the Harrow Nine's concert for parents on the day term resumed- four days after his fifteenth birthday. It would be his debut as a soloist, and was a great honour for someone only in their second year. He'd beaten at least ten older boys in the audition. Regrettably, his elder brother would not be able to be there on the 10th, because by then Mycroft would be back in Mexico City; in fact, he'd be flying back on New Year's Eve.

"You always miss anything that's important for me," Sherlock had grumbled, and gone off in a fully fledged teenager's sulk.

The criticism stung a bit, in part because Mycroft knew it was justified. He'd only managed twenty seven days in the UK in the past year. He'd got his promotion that took him out of the backwaters of Belize into the Mexican maelstrom, where he'd attracted a great deal of positive attention for his political analysis of the impact of drug trafficking on corruption. Mexico's signing of the NAFTA treaty was supposed to have heralded a new dawn, but economic and political unrest in the country was perversely escalating. Due to come into effect on New Year's Day, the new treaty required the privatisation of communal land of the indigenous peoples- and Mycroft had briefed the UK consulate that he fully expected an armed revolt by the EZLN, the Zapatista National Liberation Army, in the Chiapas Lacondon jungle areas. Even getting a week back in the UK had taken some doing.

"Sorry, brother mine, but duty calls. I can't be there on the day, but I can help you rehearse." So, the pair had taken up residence in Parham's music room and played- Mycroft on the piano and Sherlock on the violin. It was the first time the two had practiced together since their mother had died.

" _Molto espressivo_ , Sherlock." They were in the midst of the second movement, the adagio. The slow interplay between piano and violin was supposed to sound slightly melancholic, but Sherlock was rushing the music, so it sounded more cross than wistful.

"You're playing it slower than Dieneson does."

"Who's he, if I may be so bold as to ask?" Mycroft couldn't resist the sarcasm.

"Sixth former; he's just got a place at the Guildhall School of Music next year."

"So, any good?"

Sherlock smirked. "Better than you."

Mycroft sighed. "Of course he is. He's probably spent hours practicing. I am lucky if I sit down at a keyboard twice a year."

"Your choice." He lifted his bow. "From the top of the page."

Mycroft knew this was yet another dig at him. Unlike Sherlock, he needed to see the sheet music to be able to play a piece. His Mind Archive was far too full of important things these days to waste space on something related to recreation.  _Maybe someday._

Now three years later, so much had happened since then that it was hard to put it into words. Their father had died, Sherlock had finished school, been accepted to Cambridge but then run away, spending six months homeless on the streets of London. When Mycroft finally caught up with him, Sherlock was an under-aged drug addict, picked up by a police sergeant who had called social services. Two and a half months' rehabilitation in the Priory hospital meant that the boy was at least talking to him now. The concert was supposed to be a confidence-building measure, according to Doctor Cohen, helping him get ready for release.

But, Sherlock hadn't even lasted until the interval before Mycroft knew it was a disaster. He'd felt his brother's discomfort from the first bar of music, and his agitation only seemed to get worse as the German violinist and her pianist began to play sublimely. Half-way through the adagio, Sherlock excused himself and went to the Gents. Suspicious that his brother might try to bolt, Mycroft wondered if he should leave the box to follow him. After nearly ten minutes of waiting for him to return, Mycroft's anxieties got the better of him and he went looking for the boy, fearing the worst- that Sherlock had faked this and was using the time to escape. Instead, he'd found his brother locked in a stall in the loo, in the middle of a full meltdown.  A hasty call to the chauffeur and then a silent trip home, followed by Mycroft's apology. 

"You're an idiot."

Sherlock lifted his head from his knees to deliver his verdict, letting Mycroft see the traces of tears, their moisture silvered in the dim light of the bedroom.

Mycroft sighed. It wasn't supposed to end this way. He thought back to his conversation with Esther Cohen three weeks ago.

"He's making real progress," she had said.

When Mycroft didn't respond, the petite psychiatrist offered him as encouraging smile.

He used a raised eyebrow to communicate his scepticism.

"Really. I  _know_  that he's still being difficult with you. But, if that's Sherlock's preferred method of engagement these days, at least he is talking with you now."

The conversation had taken place in Doctor Cohen's London office, 8.89 miles south of the Priory clinic, if one used the A400, and 11.2 miles if the car went via the A41. Her office was exactly 3.44 miles from his townhouse. It was a further 1.32 miles to his current office at Vauxhall. After enduring a Sherlock-sized hole in his psyche, burned there by the six months of his brother being missing on the streets of London, Mycroft drew some comfort in knowing specifics such as this. At any time of the day or night, he knew exactly where his brother was, relative to his own position, and it helped him to relax just a little bit. He knew that there was something more than bordering on the obsessive about this, so chose to keep it to himself.

Esther was smiling kindly. "Really, we need to talk about re-entry."

His face must have betrayed something of his concern at her use of the word. He forced himself to take a few breaths, to quiet the instant sense of panic, and return his demeanor to its normal bland expression.

"Mycroft, you need to think carefully about what happens when he is released. The clinic doctors have put him on the exit track."

He knew this already, but didn't let on. The audio surveillance device that had been placed in Sherlock's room caught the occasional conversation with a carer about the 'action plan' to free his brother. Mycroft had thought about trying to bug the therapy room, but decided that might be a step too far. That would catch conversations with other patients, and cause real problems if it were ever to be found out. But it didn't reduce his compulsion to  _know_  what was going on with his brother. That compulsion had grown to the point where he'd called the switchboard at the Priory once too often, making a nuisance of himself. The clinic doctor treating Sherlock had politely asked him not to harass the staff, so Mycroft had been forced to find another way to satisfy his need to know.

The psychiatrist was waiting for a reaction. He schooled his voice to cover any evidence of his anxiety. "Do you think he's ready to leave? Won't he just…run away again?"

She gave him a steady look. "Not if he learns that it isn't necessary. We need to take steps to build his confidence at being able to handle life outside the clinic. That means a schedule of day release activities- supervised, of course- but opportunities to enjoy some freedoms. He needs that opportunity if he's going to be ready for university at the end of September."

Mycroft felt the serpent of anxiety starting to unfurl in his bowels. The idea of Sherlock being at liberty in London this summer and then Cambridge in the autumn terrified him. He'd spent too much of the past year living under the stress of not knowing if his brother was even alive. With Sherlock safe in the Priory, some of the anxiety had eased, but he couldn't let up.  _The stakes are too high._ Not with Ford lurking in the background, intent on playing puppet-master.

The psychiatrist's dark hair was beginning to show more flecks of grey-  _salt and pepper_. The phrase crept in from somewhere in his Mind Archive. Mycroft shoved it away.  _I need to concentrate._

The only way he would be able to let Sherlock leave the Priory was under continuous surveillance. He'd have to contact Philip Ranger at Research Associates to arrange a tail during the day release sessions. Finally, his tongue re-engaged with his brain and he managed to ask, "What do the other doctors say about his ability to cope?"

She allowed her puzzlement to show. "Sherlock's got his anxieties under control. The medication helps, and he's being co-operative. We've started to taper it off now."

The twist in his gut tightened, feeding off the conundrum. He genuinely wanted Sherlock to recover, while at exactly the same time as being extremely nervous about him being released. Mycroft swallowed, trying to push away the worry that he knew was making him slightly irrational about this.

"Mycroft? Are you alright?" There was now more than a trace of concern in Esther's tone.

He gave her a rather strained smile. "Sorry, Doctor Cohen….miles away. I'm rather preoccupied with work these days." It wasn't a lie- faced with his bastard half-brother Ford every day in the office, the conflation of his professional and personal life just added to the stress of it all.

"You look tired. Would you rather we continued on another day?"

"No, no. Please continue."

She took a breath and for a moment, he thought she might argue with him. But, then she continued, "As I was saying, you need to decide where he is going to live."

His brow furrowed. "Parham, of course, until the end of September anyway. There are people there who can look after him."

Esther shook her head. "Not a good idea. I know he doesn't want to go back there- he's said that he loathes the place. Now that you're living at the townhouse, you should consider him spending the rest of the summer there. In London, he'll have access to libraries and to galleries, music- be able to enjoy what he kept away from for fear of being found. Staying in London means that he can see me regularly, too. But, this isn't just about him; it's about you, too. This is an important opportunity for the two of you to…" she hesitated and looked thoughtful. Then Esther finished firmly "…it's a chance for the two of you to establish some sort of relationship before he goes off to university."

"But I'm working- and the hours are long, Doctor. I have to be away overnight on occasions."

She nodded. "Yes, but it's not like he'd be alone, is it? Your chauffeur lives on site, I believe, and there's Miss Forster. He knows her well; after all, he spent every Harrow  _exeat_  there, rather than Parham. And you being away at work isn't a problem- I mean, he needs to learn how to be responsible for his own time, keeping himself occupied but following a routine of mealtimes and sleep. When you get home from work, you can talk, or…" She ran out of steam. "What did you two do together when you were younger?"

He looked askance. "Seven years' difference in age, Doctor- it matters. When he was little and wanted to prance about being a pirate, I was studying Greek texts. We didn't exactly  _play_."

Esther cocked her head. "I distinctly remember that first summer, when he was ten and I came to see him at Parham, you and he were playing board games of all sorts- Cluedo, Operation, chequers- you even taught him chess, if I recall."

Mycroft remembered. "In desperation. By the end of that summer, we'd made up our own sets of elaborate rules for all those silly board games to try to keep them even moderately challenging. That was the first time that I really understood Sherlock's genius. But you don't need me to tell you that he'd laugh at the suggestion of something so childish now, Doctor."

"Fair enough. But you still have interests in common- take music, for example."

It was his mother's deathbed plea, "Just find ways to connect with him." Mycroft had always thought music might be one such way. On the occasions when he was on home leave from his overseas postings and Sherlock was home from school, music had been one thing that they had been able to talk about. He played piano; Sherlock violin- at least there was a huge repertoire of sonata music from which to choose.

That had been his justification for choosing the concert tonight. "Take him out of the Priory for the weekend; do something together," Doctor Cohen had said. So, he'd managed to get his hands on the impossible- a private box, so his brother would not have to deal with crowds. No need to stress him on one of his first nights out. The idea was a concert, followed by a late supper at the town house, and then what the Priory doctor had called a "sleepover", just to help acclimatise Sherlock to the idea of being elsewhere at night. Maybe on Sunday, he could take him to a gallery.

Now looking at the wreck of his brother's face looking at him in the bedroom, Mycroft knew the depths of his mistake.

Sherlock didn't bother keeping his distress hidden. "How could you be so cruel?  _That_  piece, of all the music in the world. If you wanted to remind me of everything I lost when I broke my wrist, you couldn't have chosen better. Watching her play was torture, knowing I will never, ever be able to play as well as I used to." The raw pain in the boy's baritone told him just how wrong Mycroft had been.

"Sorry, Sherlock. Fair enough. I didn't think, which makes me an idiot."

"No." Sherlock's expression shifted into confusion. "I wasn't talking about  _that_. You're an idiot, because the saying you just used is wrong"

"I'm not following you."

Sherlock gave a histrionic sigh. "For someone who thinks he's so clever, you're really stupid when it comes to chemistry.  _Pouring salt onto a wound_  actually helps to heal it, not the other way around. It might hurt and sting- that's the positive ions of the sodium chloride at work, making the nerve cells fire. But that's irrelevant- the antiseptic attribute of sodium chloride is why doctors use  _saline_  solutions to clean up wounds."

Mycroft sighed. Trust Sherlock to use chemistry to deflect attention away from what was really bothering him.  _It's going to be a long weekend._

oOo

 **Author's note** : _This is set the day before the opening scenes of TSiB._

"What is it?"

Lestrade was standing in the mortuary, looking extremely bedraggled. He was soaked to the skin, But that wasn't the worst of it. The scent of decomposed flesh was so strong that he was trying desperately not to give into a rising tide of nausea. How the pathologist and Sherlock could stand it, he'd never be able to understand. When Greg moved closer to look over the taller man's shoulder, his shoes squelched.

"Stay back." This warning was growled by Sherlock, who was bent over a strange looking bundle – something just under two feet in length, wrapped in lengths of dirty beige cloth strips. The consulting detective was using a pair of tongs to remove the strips slowly, after soaking them in alcohol. There was a metal tray on the table into which he dropped the first length of cloth.

"Why? Do you think it's something dangerous?" Lestrade sounded slightly concerned. "Should I call the Haz Mat guys?"

There was a snort. "No. I just don't want you getting this wet with water. Someone has gone to a great deal of trouble to keep it  _dry_." He kept working.

The DI stepped away, backing towards the second dissection table, on which a badly decomposed body lay. He took a sniff and decided that discretion required him to move in a different direction. Molly had already done the autopsy. "Infection or poison, can't tell which- but it got in from a small wound in the victim's hand."

Sherlock's response was simple: "Infection."

Lestrade's retort was equally brief. "Then why didn't the antibiotics we found in the house work?"

Swabs had been taken, and the pathologist was now working in the corner to analyse them and tissue samples to try to identify the cause of the infection- or poison. She wasn't convinced yet.

if it was infection, this sort of death might have raised nothing more than a routine medical investigation, except for the circumstances in which the man had been found. When Reggie Shaffer not been seen for nearly a fortnight, the family next door started to notice a horrible smell coming from the man's shed at the end of the garden. When the neighbour used a tyre iron to force the lock, what he found made him immediately call the police.

When Lestrade took one look at the inside of the shed, he'd immediately called Sherlock, despite the protests of his Forensic Crime Scene Examiner. "He'll wreck the chain of evidence; we don't need him" whined Anderson.

Once on the phone to Sherlock, Lestrade explained, "You specialise in weird, and this is the oddest thing I've seen in years. The walls of the shed are painted with murals, like something out of King Tut. Apart from a table against the wall with some pretty bizarre things on it, there's no other furniture in the room except a sarcophagus- you know, one of those great big wooden coffin things with a pharaoh painted on the top. And the body's on the floor beside it. It's pretty gross. Looks like a film set, except this guy is  _really_  dead."

"Don't let Anderson mess anything up. I'll be there in ten minutes."

The DI noted the singular pronoun. "Where's Watson?"

"Dublin; some medical conference."

By the time Sherlock got there, it was pouring with rain, and the shed was crammed full of forensic people processing the scene. Lestrade was standing outside, getting thoroughly soaked, when Sherlock arrived, bearing an umbrella.

Greg was surprised at that. "I've never seen you with an umbrella. What's the occasion?"

"Mrs Hudson shoved it into my hands as I went out the door. Said I was going to ruin my coat if I got it soaked again."

That made Greg smile. That was Sherlock all over- didn't give a damn about getting wet himself, but would take precautions to protect his beloved Belstaff.

After a look from the threshold, Sherlock closed his umbrella and put it beside the door, lifted the yellow tape and walked straight to the table at the back and looked at the odd instruments lined up on the top. He ignored the body, which was being photographed by Philip Anderson.

"Anyone look inside the sarcophagus yet?" He was holding up a long thin piece of metal with an odd hook at the end.

The Crime Scene Examiner shook his head. "The body takes priority."

Sherlock slid the heavy wooden top sideways and used his mini-maglite torch to explore the inside of the coffin. "Maybe for you, Anderson, but the more  _interesting_  items are in here." He reached in and started to remove something.

" _HOLMES!_  Don't move anything before I've photographed it! _"_  Anderson's shout brought Lestrade into the shed from where he'd been outside, questioning the neighbour, and getting even wetter in the process.

The Consulting Detective sighed, but put whatever was in his hand back in place. Through gritted teeth, he snarled, "well, get on with it then. I haven't all night."

Anderson pushed by him and peered in. The camera came up to his face and then a rapid fire series of flashes lit up the shed. When he stepped back, he looked straight at Lestrade. "See what I mean? The evidence needs to be treated with respect."

Sherlock snarled, "Oh, I do treat the  _evidence_ with respect; I just don't bother doing the same with you."

"Leave off, Sherlock. No need to make this even harder."

Four hours later, they were at Barts, where Sherlock was finally able to get to work on the two items that had been left in the bottom of the sarcophagus. As he pulled another strip of cloth off the bundle, he muttered, "stupid,  _really_  stupid."

Trying not to gag at the stench from the body, Lestrade asked the obvious question. "Why did you say these were more interesting than the body?" He gestured to the bundle and the oddly shaped jar beside it.

Sherlock smirked. "Because I think this is the cause of death."

"Is the poison in the jar, or is that... miniature mummy hiding a murder weapon?" Lestrade didn't hide his disbelief.

"Who said anything about a murder? Did you hear me say this idiot is anything other than the victim of his own stupidity?" Sherlock kept working off the strips of cloth.

As the last bits were removed, Lestrade realised that the bundle was the dried out body of a small animal.

"What the hell? Is that a  _naked cat_? How could a cat kill Shaffer?"

At that word, Molly came over, curious. "Umm…yes- it's a cat, but it looks as if it's been embalmed."

Sherlock was smiling as he used his pocket magnifier to examine the body of the cat. "Behold  _Felis silvestris catus_ , which in ancient Egypt was called  _Mau_. The bodies of temple cats were routinely mummified to honour the goddess Bastet. You'd best get Sergeant Donovan to ask whether Shaffer had a cat, and, if so, when they last saw it."

"I don't care if it's a moggie from Maida Vale, how could that kill a human being?"

"It didn't….not exactly." Sherlock turned towards Molly. "Anything conclusive yet?"

"It's still searching the database….Sorry."

"You can narrow the search down. Check for one of the  _staphylococcus aureus_  bacteria. It could be MRSA."

She hurried back to the PC and started typing.

Lestrade was getting a headache. If it wasn't the stench of the decayed body, it was the nonsense that Sherlock was spouting. "Out with it. What does this… prop from a bad costume drama set in Ancient Egypt have to do with the dead body?"

Sherlock grinned. "Sodium. That's the cause of death."

Lestrade rolled his eyes. "Now you're telling me the guy was killed by salt?"

"Not just  _any_  salt. Natron. Ever wondered why sodium is labelled as Na on the periodic table? Natron. Do you know anything about the process of mummification, Lestrade? It's actually quite interesting. First the body is washed in alcohol- palm wine is the traditional version, and then rinsed with water. Then an incision is made…just here." He pointed to a dark spot on the cat's body. "Then the internal organs are removed, because they deteriorate first. They are packed in natron- that's a natural salt found in the Wadi Natron area of Egypt, consisting of four forms of sodium- mostly sodium carbonate decahydrate, and sodium bicarbonate with traces of sodium chloride and sodium sulphate. The organs are inside the Canopic jar." He pointed to the odd shaped receptacle. "...perfectly preserved. Remember that instrument with the little hook that was on the table at the back? That's jammed up the nose into the brain cavity where it's used to mash up the soft tissue so it can be poured out through the nostrils."

Lestrade was beginning to feel even sicker to his stomach, if that was possible.

"The body cavities are then packed with natron, and the whole body is covered with it, too- for forty days. Then it's washed off, the skin- or in this case the pelt- is oiled, and then the cavity is re-stuffed with dry materials- probably straw- to keep its shape and then the wrapping is done; each strip is coated with resin, which has to be dissolved to remove it."

Lestrade looked hard at Sherlock. "This is just plain too  _weird_  for words. How do you know this stuff? _"_

Sherlock grinned as he started to open the Canopic jar. "Miss-spent youth. I once tried to mummify a dead pheasant, just to I see if I could. Think of it as an  _applied_  history and biology lesson."

Lestrade pinched the bridge of his nose. "Sherlock, tell me what this has to do with the stinking heap of rotting flesh lying on the next table."

Sherlock smiled. "That's the easy bit. The wound that Molly found on his hand was probably caused by Shaffer's mishandling the tool used to remove the brain. If you look carefully at the wound area on his hand, you can see that he packed it with natron, thinking that the sodium salts would sterilise the wound and help it heal. "

Molly arrived at the table wearing a big smile. "You were right, Sherlock- tested positive for MRSA. Which means all of us need to decontaminate and sterilise everything before we go."

Sherlock gave Lestrade what the DI called his "know-all" smirk.

"There are many types of s _taphylococci_ , but most infections are caused by the  _aureus_  group- of which MRSA is the best known. It's common enough- grows on the skin and nose of about a third of the world's healthy people without a problem. Most bacteria are killed by strong contact with salt, so Mister Shaffer probably thought he was doing the right thing by pouring natron into the wound that he got on his palm when he was embalming his cat. Trouble was,  _staphylococcus aureus_  are one of the very few bacteria that actually  _like_  salt; so his attempt at self-medication killed all the good bacteria- the ones that promote healing. His stupidity removed the competition for the MRSA, which colonised the wound and got into his blood system. About a week later, he was dead of multiple organ failure."

Molly was listening with rapt attention. When he finished, she giggled and bit her lower lip. "So, there's truth in the old saying, don't rub salt into the wound."

Sherlock shook his head. "Not always. Doctors use saline solutions to clean wounds. Salt can be both kill and cure." He looked at the mummified cat. "…in more ways than one."

Molly giggled again. "Cured…I get it, like salt beef, not just healing."

Smiling, Sherlock continued, "So, not a murder, but rather accidental death, complicated by stupidity. I expect you will find that Mister Shaffer's last will and testament asks for him to be mummified, but no embalmer in the UK will do it. It's too  _dangerous._ "

Lestrade shrugged. "Not my problem. Accidental death is one for the coroner to decide, based on your evidence here."

Rather shyly, Molly added, "Thanks, Sherlock, for the history lesson, not to mention biology."

Sherlock smirked. "Both are  _chemistry_ , Molly."


	2. Part Two

**Summary for the Chapter:**

> Sodium is named after sodanum, the Roman word for glasswort, a plant whose ashes were used in the making of glass. Sodium carbonate, also known as soda-lime, accounts for about 90% of manufactured glass. About two kilos of sodium carbonate is needed to create every ten kilos of glass. Different types of glass are then made by adding other elements to it, with colour and transparency varying from clear to totally opaque, and strength varying according to how it is manufacturing.

"There are five things you need to do, Mycroft, when Sherlock is released at the end of the month. They may not be easy, but you need to bear them in mind."

The psychiatrist was sitting across from him, in the conservatory. It was on the street level floor, but at the back of the South Eaton Place townhouse, which meant its glass walls had been built over the kitchen that exited on the lower ground floor. From their elevated perch, the Victorian conservatory gave them a look at the glorious sunshine glinting through the leaves of the pair of silver birch trees planted in the courtyard below, between the kitchen and the mews.

His mother had planted them seventeen years ago. One of the two trees was older, bigger and taller when it was planted. "That's for you, Mycroft." The other was a mere sapling. "That's for your new baby brother." His father had not approved. "They'll grow up to block the view from the conservatory." Violet had replied, "In my old age, I want to look out on these trees and remember them growing- much nicer than looking at some new monstrosity being built to ruin the London skyline."

When the trees were planted she hadn't known that Sherlock was on the Autistic Spectrum- just that he was a "difficult baby", according to the nanny. When Sherlock was five and it was the second time he'd gone into meltdown and thrown something hard enough to crack the conservatory glass, Violet began to realise he was going to get hurt when he got strong enough to actually break things. She had all of the original Victorian glazing replaced with toughened, tempered glass, with a plastic lamination on the inside so if he did throw a wobbly in there again, the broken glass couldn't fall in and he wouldn't be hurt.

Mycroft thought of Sherlock every time he sat in the conservatory now, and not just because the laminate had started to darken over the years. The two birch trees had grown almost as tall as each other since their mother had died seven years ago, but the second one still had a more slender trunk, and was inclined to move more in a stiff breeze. Its leaves were first to fall, and last to emerge in the spring. It had been planted a bit closer to the house. "It will need more protection," she had said. Sometimes he thought it had been a mistake to plant the two trees so close together. His mother's sentiments aside, logic said that neither tree would thrive as it might, given that they had to compete for water and nutrients.

Esther shifted in her seat, calling his attention back to the present. "The first is simple. Actually, they all are, in theory. Practice might prove harder."

"I'm listening, Doctor Cohen."

"The first thing is to be totally, and I do mean totally, honest with him. He's far too observant for his own good; and has a liar radar that is second to none. You will need to build his trust with you, so you must be utterly transparent with him."

 _Totally impossible_. There were simply too many things that Sherlock must never know- the principal one being the fact that he had a half-brother who was responsible for many of the disasters that had befallen Sherlock in the past seven months. Mycroft was far too accomplished a liar to let anything show on his face, so he nodded to Esther.

"The second thing is to encourage him to try new things- he's been institutionalised now, and may feel anxious about having too much choice. What little I can get out of him about his life style when he was on the streets seems to suggest there was a lot of routine and a great deal of avoidance of situations that involved interacting with people. It may seem easier just to try to tell him what to do, especially if he is dithering, but it's likely to be counterproductive. You will have to curb your enthusiasm for making choices for him."

Mycroft sighed. "Doctor Cohen, this sounds suspiciously like you are giving me a lesson in parenting. I am not Sherlock's parent, nor am I well suited to the role of being my brother's keeper. I lack the experience to know what to do, what to say, to help him. He'd be better at Parham, with someone properly trained to keep him company this summer. Although well-intentioned, I am apt to do the wrong thing- as I discovered when I took him to the concert."

She gave him a stern look. "Mycroft- you can't duck this, if not for his sake, then for  _yours_. You need to learn some things as much as he does. Perhaps the concert went wrong because you just assumed you knew best and didn't  _ask_  Sherlock what he wanted. You have to stop thinking of him as a child to be ordered about- he needs to be given the chance to talk over the options."

He sniffed. "Any suggestion of mine seems to provoke an immediate decision to do exactly the opposite."

She snorted. "Of course, Mycroft- he's a  _teenager_. What do you expect? Rebellion is inbred in everyone his age. This is less about what he's been through than you might think." Esther seemed genuinely bemused by his discomfort. "So, you have to restrain yourself; tell him- and yourself- again and again that it's  _his_  choice."

He frowned. "Even if he makes stupid choices? Like not eating properly, not sleeping, or worse, taking drugs?" Mycroft did not hide his scepticism about her advice.

"I'm not saying you should applaud bad decisions, just respect his right to make them. And when he makes the right ones, applaud loudly. You strike me as the type who expects perfection from everyone, and complains when it isn't there. Learn instead to encourage, rather than chastise- that's the third thing, by the way. He won't learn otherwise. If he does relapse, you need to deal with it by making him feel safe and loved enough to admit it to you."

"Actually, that's the fourth thing to remember. Mistakes happen- like yours about the concert; it's more about how you  _both_  handle the mistake than the actual error. Don't accuse him of weakness or stupidity, and just rein in that superiority complex of yours. If you are too harsh or unforgiving a judge, then he will try to hide his mistakes, believing that you will use them to put him back in hospital. He is suspicious of your motives, Mycroft, because he does not believe that you love or value him."

Mycroft was surprised at how much that accusation felt unfair. How could he even begin to explain the depths of his concern about his brother? The sleepless nights, the hours spent worrying when he was missing, the horror of realising what his elder half-brother had done to Sherlock- none of that was possible to express to the psychiatrist sitting in the wicker chair across from him. He'd not been able to tell her a single thing about that part of Sherlock's experience- it was a secret that needed to be kept from everyone- even Sherlock, who must never find out about Ford. He looked down at the black and white tiles of the conservatory floor, watching the sunlight filtering through the leaves, making a constant play of light and shadow on the floor.

"Mother once said that Sherlock needed love, but did not know how to be lovable."

That got Esther chuckling. "Yes, of course- your mother was a very perceptive woman. I only wish I'd met her. She knew Sherlock better than anyone ever has or ever will. Why bother trying to be lovable, when all you are going to get is rejected? After she died, Sherlock does not believe anyone cares about him, so he does not value himself."

"That surprises me. To hear him talk, everyone else is an idiot, and he is the only one with a brain." It was said dryly, with plenty of sarcasm.

"Again, don't mistake a teenager's bravado for real confidence. He's just figuring out who he is- it's a time when most people's sense of their own identity is a bit fragile. After playing the dutiful schoolboy, the role of a homeless junkie for six months was an exciting change. Inevitably, it's going to take him a while to learn a new role as a university student. And it's your job to make it easier for him. Have you ever wondered what it must be like to be  _your_  younger brother? Don't hold up a mirror and say to him that he has to be like you. Your glittering school record, university success, the job, the title, your self-control- you're a hard act to follow, Mycroft Holmes, and it would stress out anyone, let alone a person on the Spectrum. So the fifth thing is simple, too- cut him some slack. Let him figure out who he is, not just a reflection of you or who you think he should be." There was a little bit of anger in her voice, and he wondered at it. She was being protective on Sherlock's behalf. That made him smile.

"You  _like_  Sherlock."

Her answering smile said he'd hit the nail on the head. "Yes, I do. He was my first private patient, and he's been endlessly challenging over the years. Don't forget, I've seen more of him over the past seven years than you have, and I know that he's worth caring about, even if he'd probably snarl at me for saying so. He's …" She paused for a moment. "It's important that you learn how to love him for who he really is- for your sake, as well as his. Use this summer wisely, and just relax…I have faith in you both."

oOo

 **Author's note** : This follows on directly after the scene in  _Iron_  (Part Two), when Sherlock solved the case of the sinking ships.

oOo

After Sherlock stalked off to his bedroom once Lestrade and the Dutchman had gone, John decided it was best to let him cool off for a while. He texted Mary that he wouldn't be home tonight, because there was no way he would leave Sherlock alone in this mood. He re-opened his laptop and typed a little more of his draft blog, while he tried to figure out what the best thing to do would be. In the old days, the frustration of a too-easy case might have driven Sherlock into shooting the wall. But since his return, his attempts to deal with ennui had led him down more dangerous paths. Left to his own devices, Sherlock might be tempted to try shooting something else. A knot of anxiety formed in John's stomach, and made it hard to concentrate on his typing.

After a half hour, John decided he needed a cup of tea- and it would be an excuse to look in on Sherlock. While the kettle boiled, John wondered about how best to tackle the problem.

 _Relax_. As if he could, as if his subconscious mind was something he could control, or turn off at will. It was odd. When he lived at Baker Street, he was better able to monitor Sherlock's moods, and just go with the flow. But now that he wasn't around all the time, he spent more time worrying, thinking about what Sherlock might be doing, fearing the worst.

He went down the hall carrying the two mugs of tea. Pushing open the door with his foot, John saw Sherlock sitting at the end of the bed, but looking sideways at the wardrobe against the wall, or, rather, the mirror that was hanging on the front of it. He didn't move or speak to acknowledge John's presence.

"Tea." John set it on the bedside table that held Sherlock's reading lamp.

There was no reply. Sherlock was still looking in the mirror.

John muttered, "So, we're not talking then," more to himself than to the unresponsive man.

The doctor sighed, and started back towards the living room. Behind him, Sherlock suddenly stood up and reached behind the door, snagging his Belstaff and pulling it on in a whirl of long arms as he strode down the hall. Taking evasive action, John plastered himself against the wall to get out of the way, wincing as the hot tea in his mug spilled onto his hand.

"Hey, where you going?"

"Out." The word was snapped out in the kitchen as Sherlock slipped his scarf around his neck.

"Hold on, give me a minute; I'll come with you." There was no way in hell that John was going to let Sherlock out of his sight tonight. Not even Mycroft's surveillance tactics would be able to keep up with him- after two years of dodging cameras and Moriarty's minions, Sherlock could be invisible as soon as he stepped out the door, if he wanted to be. And right now, John didn't trust him  _not_  to want to be.

Sherlock stopped at the door from the kitchen leading onto the stairs. Over his shoulder, he looked back at john.

"Why?"

"Why what?" John had ditched his mug and was fumbling for his coat.

"Why would you want to come with me?" He looked genuinely confused.

"Uh, maybe because I came over today to spend time with you? That usually means being in the same place as you; so, where you go, I go."

Sherlock turned away. "I don't need a baby-sitter, John." This was said quietly, but with some steel in the tone.

"Who said you did?"

Sherlock gestured toward the open lap top in living room. "You have a blog to write, and a _cast iron_ excuse to get on with it."

John sniffed. "Well, you know me- I prefer actually doing something than writing about it."

Sherlock started down the stairs. "Save what you've done. I'll wait for you outside."

For a moment, John wondered if this was a ploy to get away, but then realised that to do anything other than take the time to close down the laptop would imply he didn't trust the man.  _Damned if I do, damned if I don't._

When he did make it out the front door a few minutes later, he was relieved to see his friend standing on the pavement, coat collar turned up- and a plume of cigarette smoke rising over his shoulder.

" _Oi_! You are supposed to stop smoking."

"Better than the alternative." Sherlock dropped the half-smoked cigarette, stepped on it and then strode away without a backward glance.

John had nearly to run to keep up with him- and more than once his left leg cramped at the pace. He'd managed to ditch the cane fairly quickly, but at times of stress, the limp had a nasty habit of re-appearing. The taller man made no eye contact, and didn't acknowledge his presence as they walked. By the time they had gone from Baker Street eastwards past Portland Square, John was getting annoyed.

"Slow down, will you?"

That stopped Sherlock in his tracks. "There is an answer to that, John. Take your leg home and put it up on the sofa- your own sofa- and let Mary fix your dinner."

"You're not going to get rid of me so easily."

"Who said I was trying to get rid of you?"

"Talk to me, Sherlock. Where are we going?"

They had stopped in front of a new office block, on the corner of Osnaburgh Street and the Euston Road. The four story building had floor to ceiling plate glass. Sherlock was staring at the building with a frown.

"What is it? What's wrong?"

"This used to be a one story parade of run-down shops. This is  _new_." More than surprise, there was a hint of disappointment and annoyance in that word.  _"Very_ new." He pointed to the "For Let" sign in the window, which said the building would be available for occupation in less than a week.

John looked at the building. He supposed that this sort of thing must happen to Sherlock a lot- finding things that had changed since he was away. Now dark, the windows served as a mirror, showing a reflection of the two of them standing there.

John glanced at Sherlock and realised that he was staring at his own reflection, again- like he had been in his bedroom mirror.

"What is it? What do you see?"

A shadow passed over the taller man's face- a micro-expression that moved too fast for John to actually recognise it. All he was left with was a sense of his friend's distress.

"Sherlock. What's  _wrong_?"

The image in the glass gestured, reflecting his friend's pointing finger. "It catches me by surprise sometimes. I don't _recognise_ myself. I looked different when I was away. I had to keep in role  _every_  waking moment, incognito; my disguise was literally a matter of life or death, and not just for me."

That shocked John, who looked away from the real person back to the reflection. "What…did you look like?"

Sherlock sniffed. "Norwegian." His voice had gone up an octave to a tenor, and added a Scandinavian accent, with just a hint of a lisp. "Lars Sigurson. Blond, short hair." The reflection made a gesture toward his chin. "A beard- reddish blond, trimmed short. I wore glasses, different clothes. I got used to the way I looked. Sometimes, when I catch my reflection now, I think,  _that's_  not me. It's like seeing a ghost."

Whatever John might have started to say, the words were drowned out by the sound of breaking glass. Above them and to the left some twenty feet, glass shattered, exploding into the night. As the pieces came raining down onto the pavement, something dark came out of the window and fell to the ground.

After a stunned second, Sherlock was in motion, shouting at John. "See if he's alive!" He then bolted around the corner onto Osnaburgh Street.

Without a second thought about his leg, John ran and knelt beside the figure, pulling out his phone at the same time as he reached for the man to try to find a pulse.

 _Shit._  He found a pulse alright- it was driving out a torrent of blood from a gaping wound in the man's neck. He tried to apply pressure with one hand while keying in 999.

"Hello, Emergency Service operator- which service is required? Fire, police or ambulance?"

"Ambulance, and police."

"I'll connect you now." There was a brief pause, then "Hello, London Ambulance Service, where are you calling from?"

"Euston Road, at the corner of Osnaburgh Street. An incident- a man through a first floor plate glass window. He's fallen about twelve feet and is bleeding out. Send an ambulance  _now._ " He thumbed the speaker key then dropped the phone so he could put a second hand on the wound, trying to stem the gush of blood.

"Help's on the way, sir. Keep the line open and a doctor will talk you through what you should do."

"I am a doctor!" he yelled. "Transfer the call to the police." As he bent down to try to see more of the wound, John kept wondering where the hell Sherlock was and what he was doing.

Nine exhausting hours later, he had the answer to his question. Sherlock was standing in front of an evidence board in New Scotland Yard, explaining what happened next. Lestrade and Donovan were behind him, looking at the photographs and the arrows in black pen that Sherlock had made on the white board.

"While John was waiting for the ambulance, I entered the building and apprehended the suspect."

"Yeah, we got that far, Holmes. You cornered him in the basement. Good thing for you that you could get a mobile signal down there, or we might not have found you. Of course, for all we know, the guy now in the interrogation room is just a janitor cleaning up before the building hand over. He hasn't said a word since arriving, and refuses to talk to his court appointed lawyer, except to say he's innocent. We don't even have a name, for God's sake- only your accusation that he's a criminal. You scared him witless."

Sherlock was looking at Sally as if he was considering her sanity. "Murder victims are killed by criminals, Sergeant. By definition."

Lestrade was looking at the board. "But, we don't know this was a murder. It could have been an accident. We found the guy's phone smashed on the floor- maybe he just wasn't paying attention to where he was going."

Sherlock rolled his eyes in annoyance. "We've been over this already. LOOK at the crime scene -the office tells you what you need to know."

"I am, Sherlock. That office was totally empty- no furniture, carpeting, nothing. There were no signs of forced entry or a struggle, just a few pieces of glass on the floor, from where he  _fell_  out of the window."

Sherlock closed his eyes slowly in scarcely controlled irritation. After a night of frenetic activity, he was now stationary, a solid shape fraught with frustration. "You aren't observing. That phone? It was dead- no battery life left, so he'd hardly be using it to the point of not knowing what he was doing."

"So, who cares about the phone…he must have just tripped and fallen through."

A roar of frustration erupted. " _THINK_  about what you've just said. People don't just fall against a window and have it explode out like that- this is supposed to be tempered glass, toughened so it won't break unless it's hit with something very hard. It's a  _murder_."

John's sigh was audible. Sherlock was still so volatile. "Just calm down. What we do know, is that the victim is dead." It had been a hellish night. He'd given his all to keep the victim alive, but the catastrophic wound in his neck meant he'd lost so much blood that it was touch and go. With only a few broken bones from the fall, the man was still very much alive in the ambulance and going through the Emergency Department doors, but circulatory collapse took its deadly toll, and four hours after surgery, he'd died. By the time John got to NSY, he was tired but still keyed up. Compared to the day job of giving flu jabs and checking tonsils, the drama of the night had been exciting.  _Just like old times._  He'd washed off as much of the blood from his hands as he could at the hospital, but his shirt cuff was still stained.  _Hope Mary's good at getting blood stains out._

"We know more than that, John. We know who the victim is. His name is Robert Snettering, the construction project manager at Regent's Place. It was his responsibility to sign off on the building project and hand it over to the letting agents. We also know that the wound that killed him- the one that caused the blood loss- was made by glass; you confirmed that."

The doctor nodded. "Yeah, they pulled out bits- shards from the wound, in the ED. Technically, he died of organ failure caused by circulatory collapse, but the wound is what killed him, eventually." He wondered if Sherlock's  _need_  to find a case, a really interesting case, was leading him to concoct a theory rather than accept it might have another cause. "All that said, there's no way to tell that the wound was caused by accident or purpose."

That earned him a glower from the Consulting Detective. John stood his ground. "The evidence on the body isn't conclusive, Sherlock. It just tells us  _how_  he got the wound, not why or who did it."

"The glass tells us that."

Lestrade's face creased in frustration. "So you say, Sherlock. But without proof, there's no reason to hold the suspect. His prints aren't in the system, they aren't on the body, and they aren't in the room where the man fell. So, how can he possibly be connected? No bits of glass have been found on him- he's clean."

Sherlock paced over to the door into the large meeting room adjacent to the open space area. Throwing open the door, he snarled, "Why haven't you finished yet?!"

The round table had been moved out, and the empty floor lined with a tarp. A Crime Scene Examiner was on her knees, carefully picking up a piece of broken glass from a box and trying to figure out where it fit into the bent window frame that lay on the floor. It was about three quarters of the way complete. Another intact window panel was leaning up against the meeting room wall.

"Because it's worse than any jigsaw puzzle," the young woman complained, rocking back on her heels to look up at him.

"That's the whole point, officer. It shouldn't even be possible to reassemble this window."

She looked confused, and Lestrade just puffed out his cheeks. "Then why did you insist on her doing it?"

Sally stood in the doorway, with her hands on her hips. "A bloody waste of police time, this exercise. We can't be sure that we even found all the pieces, and in any case, what does it matter? And why the hell did you make us take the other panel out of the ground floor windows?"

Sherlock turned and zoomed in on her, bringing his head down closer to her level, like some raptor. "It makes all the difference in the world, Sergeant." He turned back and reached into the CSE's tool box, pulling out a hammer. Before anyone could react, he walked over to the clear glass window panel leaning up against the far wall and gave it a firm blow on the top left corner of the panel. For a moment there was nothing, then a pop, and the whole surface cracked into crazy paving- an opaque mass of little pieces, but none of them fell.

"This is what tempered glass is supposed to do, it shatters without sharp edges, and even if it's hit with explosive force, it stays put because of the anti-blast laminate. It's the way it's made. Tempering puts the outer surfaces into compression and the inner surfaces into tension. These stresses cause the glass to  _crumble_  into small granular chunks instead of splintering into jagged shards as plate glass creates. The granular chunks are less likely to cause injury." He pointed to the jagged pieces of broken glass on the floor. "That, on the other hand, is annealed glass- simple float glass- a lot cheaper to make, but it breaks in shards that can cut. It can be used in construction, but only in places where there is no risk to people being injured. Because of bomb threats, nobody in London uses annealed glass on the outside of buildings anymore, thanks to the IRA and the 7/7 incidents."

"Your suspect in there is a glazier- and I think he works for the company that supplied the glass. It's a scam- proper glass costs a  _lot._  To give you some idea, the Shard used £60 million pounds' worth of tempered glass, which is just over £1,000 per square metre." He pointed at the pieces on the floor. "This stuff would cut two thirds of the price off."

"Snettering must have discovered it, called the guy in and told him that he'd found out they'd supplied the wrong glass for the upper stories. The glazier just panicked and killed him." Sherlock grabbed the box from the floor beside the CSE and tipped the rest of the shards out in a great clatter onto the tarp. He poked through the bits and then snatched one piece up, lifting it high enough to see the ceiling lights through it. There was a thin line of red all along one side. "Gotcha!"

He thrust the glass shard at Lestrade, who stepped back in some alarm. "Once the jigsaw is done, you'll find this piece doesn't fit. It's from another window- one that broke earlier most probably and was replaced. Snettering showed it to the Glazier as proof that he'd found the scam. The glazier used it to kill him." He pointed with a blue gloved index finger to the blood on the edge. "That's going to be Snettering's blood- but it will also have his fingerprints on it."

John had been following the revelations with increasing surprise. "Sherlock. Why would the murderer break the glass and shove his victim out the window? Surely that would have told the world that the glass was faulty?"

Sherlock came over to the doctor and smiled down at him. "Nearly there, John, but not quite. Think about it from the victim's point of view. You've just had your throat cut and you've been left to bleed out in an empty office. No hope of getting help in time- there's no one there. You try to use your phone to call out, but your battery's dead. So, what do you do? Use it to smash the window you know is faulty and hope you'll survive the fall. He nearly did- he had the good fortune to land twenty feet away from a trauma surgeon."

There was both a knowing look and compassion in those blue grey eyes that told John a lot. That his friend knew how much the adrenaline of trying to save the patient mattered, even if losing the patient hurt. And John saw a man comfortable in his own skin, challenged by a case worthy of his hungry mind. A moment of silent understanding passed between them. The Consulting Detective was back. This was the work that grounded Sherlock in the here and now, as himself- not some blond-haired, blue-eyed Norwegian criminal. John returned the smile.

Then Sherlock whirled around again to face Lestrade and Donovan. "So get in there and tell the suspect what you  _know_  who he is and what he did. And then get onto the construction company to find out who had the contract to supply glass. You'll get the evidence you need to break his silence."

"Okay- you've convinced me." He nodded to Sally. "You know what you've got to do."

Once she'd left the room, Lestrade turned back to Sherlock and John. "You two… It was just kind of amazing that you were walking along at just the right moment to catch this thing. Crime seems to find you, somehow, even when you aren't looking for it."

"Who says we weren't, Lestrade?"


	3. Part Three

**Summary for the Chapter:**

> The chemistry of sodium is dominated by the +1 ion Na+. Sodium salts impart a characteristic orange/yellow colour to flames and orange street lighting is orange because of the presence of sodium in the lamp. Sodium hydroxide (NaOH), also known as lye and caustic soda, has a pH of 14, extremely alkaline, which readily dissolves protein, and emulsifies oils and fat, causing terrible burns if not handled properly. Sodium has become a tool of the criminal and of those who fight crime.

**Notes for the Chapter:**

> The clues are there in the broadcast episodes- even the first one: "I worry about him constantly." This is what is known as dysfunctional protectivism, and it is a symptom of OCD personality. If you remember the line in HLV, when Sherlock saw 221b's door knocker ("He's straightened the knocker. He always corrects it. He's OCD"), this is the backstory. OCD is a complicated disorder that often begins for the sufferer in their early twenties. This is Mycroft's experience of it.

_Twelve days and counting._  Mycroft could tell you the total in hours- two hundred and eighty one from the present moment or sixteen thousand eight hundred and sixty minutes- until the appointed time when he and Stimpson were due to arrive at The Bourne in Southgate to collect Sherlock. Despite the hiccup of the concert, his brother had convinced Esther Cohen and the doctors at the Priory Hospital to release him from care. Over the past month, Mycroft's anxiety levels had been rising in direct proportion to the ever increasing proximity of that moment.

It was three a.m, and Mycroft was in his pyjamas and silk dressing gown, sitting in his study at the townhouse. The desk lamp was the only source of light, and it illuminated the papers in the plain folder that he had open. It contained today's report from Research Associates. More than six weeks ago, he'd got the private investigator firm to bribe one of the night nurses into providing a daily report; at night no one seemed bothered about who was checking the patient files for the therapy notes and the routine comments noted by the staff all through the day: "14.25 Sherlock is reading quietly in the common room." As a result, he'd been able to build up a mental picture of his brother's routine at the clinic. And he'd been told whenever there were issues or incidents around his interactions with the other patients and the staff.

Mycroft rationalised the decision to keep such a close eye on Sherlock.  _It's not just to protect you, brother mine. I have a vested interest in your survival, too._ Fitzroy Ford had made it clear- the tape recording commanded the price of Mycroft's support in return for him keeping quiet about Sherlock's role in the death of Stephen Mason*. Mycroft's clandestine scrutiny of the police file about the man's death revealed that the case was closed, signed off as an accidental overdose. But he knew what the police had not bothered to investigate; the fingerprints on the syringe left behind at the flat did not match the dead man's, or any on the system. Mycroft knew they were Sherlock's. So did Ford, and that was the basis of the blackmail.

So, when he'd sat down with Doctor Cohen to talk about Sherlock's release, despite his best efforts, he had not been able to camouflage completely his anxiety. Mycroft hoped she wouldn't think of him as being obstructive. He couldn't reveal that he knew all about the concerns of the clinic doctors- that would tip his hand and let her know that he was spying on Sherlock. And then he would have to explain what had happened to Sherlock, and that would lead to his half-brother- and the whole rotten disaster that compromised just about everything for which Mycroft lived and breathed.

At his last meeting with Doctor Cohen, she'd told him to "relax" as if such a thing were possible. It wasn't. He had become hyper-vigilant, always chewing over what could be done to get out of this impossible situation. Being blackmailed by Ford into backing policies that Mycroft knew to be wrong offended his sense of order and righteousness. Every time he had to turn a blind eye, or stop a critical comment, it seemed to eat away at his composure. And it was Sherlock's fault. If only he had gone to Cambridge as planned, if only he'd not been on the streets and vulnerable to Ford's manipulation.  _If only_  was burning a hole through Mycroft's self-control.

He'd always had tendencies towards obsessive behaviour. His need for order, his constant pursuit of perfectionism in his work, his discomfort when things were beyond his control- these were actually the wellspring of his success. At school and then later on the job, his intellect teamed up with those drives to make him extremely effective. Whenever he was confronted by situations he couldn't control, it was just a matter of gathering more intelligence, applying his mind to it, and the solution would appear. He'd not been bothered by taking on additional responsibilities even at a young age. He was used to it- after all, when his mother died, he'd come into the role of Viscount, and then five years later, assumed the financial responsibilities of his father's side of the family. Being Sherlock's legal guardian was a responsibility he'd willingly accepted. With responsibility came the ability to control, which helped ease his anxiety.

Until his brother disappeared from his tutor's house in Harrow, the night before going up to Cambridge. In that one moment, the caustic turn of events began to burn through his sense of order and control. The careful regulation of Mycroft's mind started to come undone. Even after his return from Mexico City, the hours turned into days and then months of trying to gain the one bit of information that would lead to Sherlock. The worries interfered with his work, because no sooner would he get into a report on some overseas activity than his mind would go off wandering, trying to figure out what he was missing about his brother's likely location. He knew his attempts to find Sherlock were robbing him of his professional concentration, and that he was losing his grip. That led him to check, double check and even triple check every piece of his intelligence work, for fear that thinking about Sherlock would have meant that he'd missed something important or failed to cover an issue to his usual standards. He was driven by the anxiety of being found wanting by his colleagues and his superiors- and of being kicked out of the very service he'd worked so hard to foster. Perversely, the more inwardly frantic he became to check and re-check his output, the more others noticed his dedication and commitment, not to mention the perfection of his work. They didn't know what lay behind it- just assumed the new post in the Security Liaison Service suited him perfectly.

It was even worse when he came home from work; the expectant look in the eyes of his driver Stimpson or of Miss Forster was enough to keep him on edge. Without even being asked, he knew that they were wondering if he'd found something new about Sherlock during the day. He hated their look of disappointment when he could give them nothing new. As he sat alone in the dining room, consuming the supper that Miss Forster prepared for him, his outward appearance would seem little changed. Internally, he was battling with intrusive thoughts about what Sherlock might be enduring out on the streets.

For the first time in his life, Mycroft began to suffer from insomnia, which didn't help his work. And he put on weight, too, as he turned to food for some sort of comfort. In a vain hope of somehow solving the problem he began following rituals each night, eating sweets for energy as he went through all the assembled information in the folder again and again in the hope of finding something new. Each page, each step in the path that might lead to him finding Sherlock was re-read and re-considered every night, in strict chronological order. For a memory like his, repeated reading made no sense, but he was driven to it, in desperation. It was almost as if he thought that not going through the nightly ritual of re-reading it would bring about the very disaster he was dreading. He knew that his actions weren't rational, and that the behaviour was unreasonable and strange, but Mycroft also knew that he wouldn't be able to sleep until he'd done it.

All that should have stopped when Sherlock was finally found. His sense of relief when the photo search by the police triggered an alert was incredible, almost orgasmic in its momentary release. Until that moment, he'd not believed it possible for people to actually go weak at the knees when hearing some news, but he'd nearly collapsed into a nearby chair when the call came through. Mycroft's arrival at the police station, and Sherlock's release into his custody and then admission to the Priory should have stopped his anxiety in its tracks.

But it didn't.

Because no matter where Sherlock was, the fact that he existed meant that Mycroft's duty of care wasn't over. Every day at work created the chance of meeting his older half-brother, Fitzroy Ford. Briefing sessions where the two men had to be present were particularly painful. When others weren't watching, Ford would allow his eyes to rest on Mycroft, a barely suppressed superior sneer on his mouth. It was as if he was taunting Mycroft, who could do nothing. He was struggling to find any evidence of the man's wrong-doings, and was growing desperate to find a way to discredit him. In his wildest moments, late at night, Mycroft fantasised about murdering the man. If only he could make Ford disappear without a trace- and without being implicated in the process. If only he could be certain that Sherlock wouldn't take his release from the Priory as an opportunity to disappear yet again. All the while, he knew that Ford was just waiting for him to crack under the pressure. Mycroft dare not oppose him in any policy matters. The one time he had tried, Ford had simply waited until they were alone in a corridor to ask, "How is our baby brother these days, Mycroft? Doing well in the loony bin? Committed another murder yet?"

Mycroft kept the five envelopes he'd been sent locked in a fire safe, in a locked desk drawer in the study. Unlike the nightly ritual with the written reports, he didn't need to see them to be able to remember the four photographs and the one recording. When he couldn't sleep, his mind wandered to re-create the scenes in graphic detail- but this time he filled in the gaps. He saw what had widened his brother's eye- its pupil blown by cocaine- and the man who had done it to him. The hand reaching under the sheet, the tongue poised over the nipple. Again and again his horrified imagination filled in the gaps, starting and finishing the actions caught in the photos. The tape recording provided the sound track of the re-runs. The sounds of his brother being sexually abused, the drug use, the death of the man who had done these things to Sherlock. The lurid scenes robbed him of sleep and he would stare hollow-eyed in the darkness, wondering how he could have failed to protect his brother quite so spectacularly.

"Just promise me..." The simple request of his mother- and he'd totally failed. Even when he'd found Sherlock, his brother's state of mind was so fractured that Mycroft could take little solace in the fact that he was at least physically safe. Sherlock's total silence for the first six weeks of his stay at the Priory screamed an accusation of failure at Mycroft. His refusal to see Mycroft was eloquent in its judgement. His little brother wanted nothing more than to run away from him. Mycroft had failed to give him the love that Sherlock needed to survive.

In less than twelve days, Sherlock would be moving into South Eaton Place, and Mycroft would be faced with his continuing failure to keep his brother safe, because he'd done nothing to stop Fitzroy Ford. Even worse, Mycroft would not be able to hide behind Parham staff, hired tutors, or Harrow School anymore. He was now personally responsible for helping Sherlock recover from his traumatic year, and to get him ready for university.

The thought of this  _terrified_  him.

While Mycroft was away at work, he had to find a way to keep an eye on his brother, without making it too obvious. As a matter of course, the townhouse was being wired- both audio and video cameras in every room. His own privacy be damned- Research Associates would be paid to keep a twenty four hour watch on Sherlock when indoors.

Outside the townhouse was more challenging. Mycroft had narrowed it down to three options. First, he could hire around the clock surveillance team from Research Associates, a series of shift workers who would follow Sherlock every time he left the house. It would be expensive, especially if he also wanted those people to be competent. His brother might well be able to spot a tail; he was observant, after all.

The second option was to recruit a body guard. That would spark Sherlock's interest-  _why_  would be his first question. Mycroft had an answer for that- it came as standard- a requirement- based on Mycroft's job. In fact, he thought he could make a strong case for the Metropolitan Police's Protection Command- the special units to protect diplomats and family members of people holding significant government positions. Given his current role in briefing the Queen, he might even be able to draw on the Royal Protection service- they were more competent than the standard SOs 1 or 6 officers.

But it wouldn't be enough. Mycroft knew for a fact that if Sherlock wanted to give someone the slip, he could. He was certainly smart enough. All three Protection Services relied on co-operation by the person being protected, and Mycroft could not guarantee that would be forthcoming from a brother who wanted to disappear.

So, another alternative was needed. In a recent case, he had called upon an obscure piece of legislation relating to criminal evidence being available upon request from a number of sources. It had allowed him to gather CCTV footage from Westminster Council's parking garages, as well as London's traffic cameras, and the Government's own cameras, protecting public buildings and targets of national interest. If it could be arranged that more CCTV cameras were put in place, and the current Government could be persuaded that it was part of the "War on Crime", then it could also provide additional oversight of Sherlock's movements. He knew just the right people in the right places- a word in the ear of a couple of London politicians, a police commissioner, a Home Office minister's Special Adviser**.

Faced with three alternatives, Mycroft chose all three.  _Better safe than sorry_.

If keeping Sherlock safe from Ford when he left the house would be hard, finding a way to share the house with Sherlock indoors would be even harder. Mycroft held few illusions about himself. He valued and took pride in his intellect, but it separated him from others. That was the way he liked it. He had his own ways, and become rather set in them. Order was crucial- nothing in the house could be out of place. Miss Forster had become adept at being able to dust and clean, replacing objects in  _exactly_  the same places. Mycroft dreaded the presence of a sloppy teenager who gave no thought to the trail of disorder and untidiness left behind him.

Mycroft knew he wasn't someone to whom others warmed. Respect was what he wanted, not friendship. He did not avoid social occasions, but used them to further his understanding, his contacts, his influence. He'd not found anyone remotely intelligent enough to fully engage his interest, so he took his pleasure instead from a range of solitary pursuits, which he could control and enjoy without anyone else creating disorder. Music did not need a companion, either to play or to enjoy the playing of another performer. Fine wine required only his educated palate to be appreciated; art was studied best in silence. Great books required nothing as mundane as discussion with someone who was poorly read and couldn't deal with the texts in their original language. He doubted that he had very much in common with his little brother. The only saving grace would be that he suspected Sherlock would be as uncommunicative as ever. That was all right by Mycroft; he  _liked_  peace and quiet, and craved solitude the way others needed drugs or drink.

Even on a professional basis, he kept others at a distance. His was a regulated mind that got its intellectual satisfaction from grappling with problems and issues that most people would find so big picture as to be incomprehensible. From the inner workings of Mexican corruption to the likelihood of a democratic overthrow of Middle Eastern client regimes that America tolerated- where others saw problems, he saw opportunities. People were employees or sources of information, if not obstruction. He loathed the very concept of "collegial" relations, and had leapt at the chance of joining the Diogenes Club where his taste for solitude was respected.

The idea of sharing his home with Sherlock- a teenager whom he didn't really know at all- posed the greatest challenge of his life. Geopolitical machinations, manipulating public policy, deflecting wars, steering economic disaster away from British markets- all those he could cope with; somehow he could keep them at a distance, where his mind would work out the optimal solution. But keeping a little brother safe and living with him in the same house?  _Caring is not an advantage._

oOo

"Are you going to eat that?"

John had turned up to see Sherlock after work, to find him glued to the computer screen and unwilling to eat the take away he'd brought. John had served up the food onto two plates anyway, taking his into the living room and sitting on the sofa to eat his. The wall behind the sofa was plastered with paper, notes, and odd bits of twine, looping between different items. As usual, the living room of 221b looked more like a junk store- furniture piled high with odd things. The doctor's eye was currently caught by a new item on the bookshelf beside the sofa, behind Sherlock's music stand- a framed box of what looked to be at this distance to be a wizened monkey's paw. If anything, Sherlock's living habits had become even more eccentric and messy now that he was on his own.

"Case, John," as if that were enough explanation. Then the brunet looked up but did not make eye contact with John, his expression slightly confused. "What are you doing here? Don't you have a fiancé to dance attendance upon?"

"She's out tonight with the girls from the surgery, talking about the wedding."

" _Boring._ "

John smirked. "For once, I agree with you. Can't say the wedding's my favourite topic of conversation."

"Second thoughts?" Sherlock had brought his right hand up to his mouth, somehow managing to look both startled and thoughtful at the same time, even though he still wasn't looking at John directly.

"No, of course not; Mary's great. The idea of being married to her is wonderful. Just wish the formal process wasn't such a nuisance. Turns out weddings seem to be a big thing to the female mind." To change the topic of conversation, John asked, "What's all this about?" pointing with his fork at the wall behind him.

As John finished his plate of chicken jalfrezi and saag aloo, Sherlock explained. The case had been frustrating for all concerned. A four month undercover operation, one of Mycroft's best men was deeply embedded in a cell of  _Jabhat al-Nusra_ , an Islamicist terrorist group normally active in Syria, but recently rumoured to be shipping chemicals from Britain to Turkey- and then smuggled across the border into Syria's civil war. What chemicals and why were the big question that Sami Al Ghafari had been tasked to discover. His work finally led last week to a Brenntag chemicals warehouse in East Greenwich. As the part of the world's largest full line chemical distribution companies, the company coped with literally thousands of shipments every day. The question was, could their online systems at the warehouse have been subverted by a terrorist cell?

None of Mycroft's people could figure out how to investigate it properly- not legally anyway, because that would involve a court order and sufficient evidence to convince a judge- which they didn't have. If they blundered about too obviously, it could jeopardise the agent's cover. So, Mycroft brought the case to Sherlock's attention, asking for his opinion. Sherlock blithely hacked the company's systems and had spent all day assessing whether there was anything suspicious going on. An hour ago, he'd concluded that there wasn't anything obvious, so he'd set about trying to see if he could devise his own fool-proof way of fooling the system and sending shipments of chemicals to the same place in Turkey.

"When it doubt, try it out. If I can figure a way to do it, then deduction says others might be able to do the same."

That statement made John think- had Sherlock spent so long undercover as a criminal himself that he was losing his sense of boundaries? "You seem to have picked up quite a few new…um…  _skills_  while you were away." He'd almost said "bad habits", but decided not to in case it sounded too judgmental. "Is this even legal? Can Mycroft give you cover, if the chemical company finds out?"

"First of all, they won't find out. Second, I don't need Mycroft. He has to have deniability. I don't- and I can't be traced." He smirked. "The criminal and terrorist battlefields are mostly online these days. I could hardly have destroyed Moriarty's criminals without being able to use their own techniques against them." Sherlock idly picked at the spinach on his plate.

After trying and failing to get him to eat anything more, John left him to it and went home, still pondering whether it was a good thing or a bad thing that Mycroft was  _relying_  on Sherlock's ability to flaunt the rules.

He decided to call into Baker Street the next day on his way home from work. Coming up the pavement, he spotted the government car waiting, and knew that Mycroft must be  _in situ_. He walked in on an argument. Based on what Sherlock had  _not_  been able to uncover, Mycroft announced that the embedded agent had just been instructed to go deeper- to get involved in the actual process. Tonight, the agent was accompanying three JaN operatives to the warehouse. His job was to get on camera the actual process of how they were subverting the warehouse system and re-directing stock to the Syrian battlefield.

Sherlock went ballistic. "You're an idiot. Your man will cock it up and get himself killed. At the very least, you should have let me be in the building when they got there."

"No need to risk life and limb, Sherlock. Let the professionals do their work."

"I am a _professional_."

"Who had to be rescued from a prison cell in Serbia."

That earned him a death stare from Sherlock and a snarled " _I'm fine"_ through gritted teeth.

When Mycroft would not budge, Sherlock stood up, stalked over and dramatically threw open the door from the living room to the stairs. He just pointed downwards, not trusting to put into words the depths of his annoyance. Mycroft left, still smiling.

John then spent more than a half hour listening to Sherlock rant and rave about how  _professional_  he'd been in taking down Moriarty's network without needing a single bit of help from his brother.

Finally, John couldn't take it anymore. "Promise me you'll let this one go."

"Why should I?"

John listed them, finger by finger. "First, because you haven't had time to research the three suspects- you're the one who always says 'do your research'- and it's going down tonight. Second, because it's Mycroft's show. Third, he just asked for your opinion, not your participation. Fourth, he has his own people. And last,"…as he ticked his thumb, "… because it's already too late, they've been in the building for hours now."

He stayed at Baker Street until ten o'clock to make sure that Sherlock stayed out of things, and then went home.

The next morning's alarm clock went off simultaneously with his phone- a text message from Mycroft's PA to both John and Sherlock:

**7.10 am Operational disaster. Our man missing, and no evidence.**

Blurry-eyed and scarcely awake, John barely had time to read it before another text arrived.

**7.11 am TOLD HIM SO. I should have been there. SH**

According to the flurry of texts sent throughout the day from the consulting detective to interrupt John's sessions with patients, a laptop from Mycroft arrived mid-afternoon, and Sherlock got to work. After his last patient appointment, John stopped by on his way home, and found him glued to a screen. As he delivered a mug of tea to the table, John lent over Sherlock's shoulder to see the orange glow of the night scenes captured on film.

"How's it going?"

"Badly. I've watched every minute of the four and a bit hours' worth of recorded CCTV footage, and there's nothing there that tells us a thing."

"Give your eyes a break; all that orange is enough to drive anyone crazy. Why does every street light now have to be orange?"

Sherlock drank his tea with his eyes closed. "Low pressure sodium street lamps are highly efficient electrical light sources, but their monochromatic orange light inhibits colour vision at night, when faithful colour rendition is considered unimportant. Image recognition software for CCTV cameras struggle, as a result."

"As well as making London hideously light polluted and creating eye-strain for Consulting Detectives."

"No plural, John. Still the only one in the world."

At seven, Mycroft arrived, and the discussion went rapidly downhill. It was like watching a tennis match, but instead of a ball, the two Holmes brothers were batting a live grenade between them.

"If it had been my operation…"

Mycroft cut him off, "…but it wasn't.  _You_  have a tendency to let things get out of control. You're too impulsive, too willing to take risks. This was a four month operation; too much has been invested for it to be wrecked by unintended consequences of a maverick like you."

"If you hadn't been an obstructive idiot and let me go there, your man would still be alive."

"You can't know that, Sherlock. There's no proof that he isn't alive. Anyway, it's pointless to discuss what ifs. What matters now is finding what happened to our man."

Sherlock looked up in the ceiling in disbelief. "Well, that's easy. He's dead. Next question?"

Mycroft gave him a sardonic smile. "Of course, you might assume that. But, there is  _no_  body. His body can't just  _disappear_ , Sherlock. It is a physical impossibility."

Sherlock resumed pacing across the wooden floor of 221b's living room. John observed Mycroft's face, as he watched his brother's progress.

Suddenly, as if he'd heard Mycroft's comment on a six second delay, Sherlock stopped and his face contorted into an expression of disbelief. "Of  _course_ , a body can disappear. I can think of ten different scenarios where I could make even  _you_  disappear. In fact, I rehearse them on a regular basis."

Mycroft huffed. "I mean in this particular situation, Sherlock. As ever, you over-generalise from a specific situation. Always so  _rash,_ so prone to jumping to conclusions."

John decided he needed to intervene, before the two of them came to blows. "Mycroft, you could have missed something. This situation wasn't exactly easy to keep under constant watch, even for someone as nosey as you." John hoped the trace of humour might deflect some of Mycroft's ire onto him, especially as the man was a little sensitive about the size of his nose- more prominent than that of his brother.

Pinning the doctor to his chair with a steely look, Mycroft answered, "On the contrary, Doctor Watson. Our surveillance did what it was supposed to have done. But, at some point, when they were inside, our agent must have had his cover blown in some way. He has literally disappeared. Not to be found. No trace- as even my brother has seen." With a dismissive wave, he gestured to the laptop.

John smirked. The very idea that someone might have subverted his omniscient surveillance was unheard of - tantamount to treason in the Mycroftian pantheon of crimes.

Sherlock rounded on his brother. "It's a big site - over 1100 warehouse pallet spaces, one entire acre of external storage and a tank farm capacity of 368 tonnes. Even for your cameras, big brother, that's rather challenging."

"Nonsense. As you saw, we narrowed the target down to a single one of the six warehouses on the site, and prepared the ground well in advance with extra hidden cameras, so there was no way for someone to just waltz out without us knowing. We had a live feed set up piggy-backed from the company's own internal cameras."

Sherlock was now standing between the coffee table and the sofa, his back to John and Mycroft. His attention was on one of the sheets pinned to the wall. He sniffed. "You're not looking for the right things, in the right place."

Mycroft rolled his eyes. "There is no hidden trap door, no tunnel, no secret room for you to unlock, brother mine. The place is  _clean_. Our experts have spent the whole day in there trying to find something, and not a single clue has appeared. Unless you know something different."

John tried to intercept Sherlock's inevitable riposte, but didn't get in quickly enough. Sherlock marched straight over the coffee table and stood glaring down at his brother.

"I've looked at your CCTV evidence from every angle. At five thirty five your man and three others go into that warehouse- and don't come out when the rest of the workers in there knock off for the day at six thirty." He pointed to the printed map of the Brenntag site that had been taped to the mirror over the fireplace. "The site's gates on Tunnel Avenue are locked at seven, after the four man security team arrive. Their own internal CCTV records show no sign of the JaN four in there- that's the weird part. Your coverage shows them entering, but Brenntag's footage doesn't show them at all."

Mycroft shrugged. "Their security system was obviously compromised."

Sherlock rolled his eyes. "D'uh."

Annoyed, the elder Holmes snapped, "That's an annoying Americanism that you must have picked up while on your little gap year adventures. Cease using it, immediately."

"Does it irritate you, Bro? Glish. No need to tweak."

Mycroft looked askance. "As I was saying, the warehouse has been examined by the best forensic team in the security services. Nothing. The in-house security guards patrol the buildings in sequence and watch the closed circuit screens. We've been over their footage and it appears to be genuine- we've found no traces of it being altered. The guards reported  _nothing_  out of the ordinary. Our CCTV shows the three JnA men leaving the warehouse at nine thirty eight, minus our man. We tracked them down to the riverside path- Olympian Way- there are only a few cameras down there, but the street lights made it easy for my men on the ground to follow them as they headed for the O2 arena. Unfortunately, it was a busy night- some sort of rock concert on." His face contorted in disgust at something so plebeian interfering with his operation.

"Alas, once in the crowd they must have changed clothes, and when the concert ended, somewhere in the twenty thousand people attending, our three targets disappeared from CCTV footage. We lost them."

Sherlock sniffed. "Not  _we_.  _You_ lost them- and have misplaced your agent, too. Rather careless of you, don't you think?"

"I am not in the mood for your one-upmanship, Sherlock. Just solve the case."

Sherlock smirked. "You know I hate repeating myself, but when you don't listen, then I have to- you are looking for the wrong thing in the wrong place." He resumed pacing, now steepling his hands under his chin as he walked.

The extent of Mycroft's discomfort became clear in his slightly defensive tone; "We've looked  _everywhere_. There is not one single barrel missing or a seal broken. Everything in the warehouse has been examined and  _nothing_  is other than exactly what it should be. Nothing as obvious as a body stuffed into a barrel or a box. Every item has been checked and re-checked. Nothing on the external CCTV footage shows that a body could have been moved- no bundles being carried, no suspicious weight gains if the agent had been dismembered and body parts distributed amongst the three who escaped. My people got into the warehouse fifteen minutes after they left, and there was nothing in the shed that should not have been there- with the notable exception of Sami al Ghafari."

John decided to stick his oar in. "Vanished into thin air? What about someone hacking your CCTV cameras? What about blind spots? Not even  _you_  can see everything from every angle all of the time. After all, Sherlock can make it across London without you being able to catch him on camera. Maybe Sami is just as good; maybe he's gone native, become a double agent and was just lying low until your lot cleared off."

Mycroft shifted his annoyed glare from his brother to the doctor, and gave him a strained smile. "Not even Sherlock could have avoided this level of scrutiny- we had that warehouse under surveillance lock-down. And we had boots on the ground, too. Once we got in, the warehouse was swept with thermal imaging that would have caught anyone trying to hide; even a body that recently killed would have enough residual heat to register. No expense was spared."

"Ooh,  _real_  people watching you cock it up, despite spending a fortune in taxpayers' money. The oversight committee will not be amused." Sherlock sounded almost gleeful.

Mycroft's eyes turned reptilian cold, and utterly devoid of humour. "Indeed." He sniffed. "So, Sherlock, solve this little conundrum, if you will. I haven't got all night."

"I don't suppose you checked the drains?"

Mycroft rolled his eyes. "There's only one- in the staff room basin and it isn't big enough for even a teaspoon to go down, so someone couldn't use it to hide in or escape through. Try again."

"Don't have to. The drains are the key, although there will be no trace of anything out of the ordinary."

"What are you talking about?"

" _Pozole_."

Mycroft looked confused. "What does a traditional Mexican pork stew have to do with Islamicist terrorists?"

"It takes several hours to make a  _pozole_ , which is why the Mexican drug cartels use it as the name for disposing of bodies chemically."

John couldn't help but ask. "You think the agent was killed and his body put into acid?"

Sherlock sniggered. "Not if they were in a hurry- alkaline solutions are quicker than acids. Mycroft, did your people check to see if there were tea mugs and a kettle in the staff room? If so, then then check the kettle. It's probably a catering pressurised kettle, so it will boil quicker- takes less break time. Check it for sodium hydroxide- that's lye to a layman like you. If you heat it to just over a hundred degrees centigrade, a lye solution will melt a body in a plastic barrel to a coffee-coloured liquid the consistency of mineral oil in just three hours." He was smirking at the look of distaste on Mycroft's face. "It was an American, Adolph Luetgert, known in his day as the "Sausage King of Chicago," who invented the method when he dumped his wife into a boiling vat of lye in 1897, then burned what was left."

Mycroft shifted in the chair. "Sherlock, your obsession with chemistry is rather macabre at times. Spare me the disgusting details. It sounds rather far-fetched."

"You probably won't find any evidence of the liquefied remains in any drain; they would have taken care to flush it with water. The agent's clothing and personal effects could have been re-distributed between the three men and carried out without attracting notice. But, if you check the tea supplies, you just might find something other than spillage from the sugar bag. The alkaline hydrolysis process leaves calcium phosphate from teeth and bones that become very brittle. They can easily be crushed into fine white granules, which were most likely flushed down the drain after the liquid. But it would have had to be crushed first, so you might find trace on the counter with the tea things, or in bowls or even mugs if your people look carefully enough. Also, if you're lucky, Sami will have had dental fillings; if so, then these might still be in the drains, caught in the s-bend."

Sherlock was smugness personified. "I've done it myself, here in Baker Street."

John's face must have shown his shock.

"It was that time you kept complaining about the body parts in the fridge, John. I was about to go to St Petersburg and knew that the samples would spoil before I could get back to finish the experiment. So, I just relied on the fact that the hydroxide anion in drain cleaner -which is mostly lye- is a strong proton acceptor."

Mycroft began to roll his eyes. "Tedious detail, Sherlock- just get to the point."

Undeterred, Sherlock continued his chemistry lesson. "That means sodium hydroxide strips hydrogen atoms off organic molecules to form water, which lowers their melting points, pushing the body's triglycerides into fatty acids, saturated fats are turned into unsaturated fats, alkanes become alcohols. Sodium salts are  _always_ water-soluble, so the resulting sludge is easy to flush down the sink."

Sherlock gave John a thoughtful look. "However, I did have to rush the last stages before you got home, and managed to damage one of my shirts with a splash that also caught my wrist." He unbuttoned his shirt sleeve and pushed up the cuff. Pointing to a scar, he continued, "And that's how you will find the culprit, most likely. Get one of your agents to take a good look at the crowd that Sami was running with; the one with the lye burn is your guilty party."

"And, brother mine, my  _obsession_  means that I also know what will lead you to the way the chemical orders are being fraudulently re-directed by the terrorists. Trace the arrival of any barrels or containers of sodium hydroxide at the depot in Turkey. One of them – about twenty liters worth- will have been accounted for coming into Brenntag, and there will be a record of it going out at some point yesterday. The Turkish destination and the end user address will be key- they wouldn't dare send an empty or faulty barrel to a real customer. Find it, and you will find it full of water to hide the fact that the contents were changed- and the route it took through the computer system will solve this case."

The elder Holmes got to his feet and started putting on his coat.

Sherlock continued as his brother picked up his umbrella. "Adequate theoretical chemistry, but sloppy execution will reveal your criminal- to someone who knows what to look for and where to look for it. Goodnight, Mycroft- a simple thank you will suffice."

"Thank you, and goodnight, brother. Don't play with any nasty chemicals, will you? Mrs Hudson won't approve of you clogging up the pipework. And you already have enough scars to last a lifetime." He picked up his umbrella and the laptop, and started down the stairs.

**Notes for the Chapter:**

> *The story of Mason and Sherlock is told in Periodic Tales Holmium.   
> **The UK leads the world in the use of CCTV cameras in the fight against crime, and has one of the densest per capita number of cameras in the world. Between 1994 and 1999 the Central Government made £38.5 million available to 585 schemes nationwide- with the majority of new cameras were placed in London. During the 1990s, 78 percent of the Home Office crime prevention budget was spent on implementing CCTV and a further £500 million of public money was spent on CCTV between 2000 and 2006. In 2003, it was estimated that there were 4.3 million cameras in the UK, with over a half million of those in London. After that date, London introduced congestion charge cameras, so every significant street is now monitored by camera, and the number of cameras used on the London Underground and London buses has doubled over the past decade.
> 
> Now we know why.


	4. Part Four

**Summary for the Chapter:**

> Lethal overdoses create cardiac conduction blocks and disruption- life-threatening ventricular arrhythmias, myocardial infarction or ischemia, which are caused mainly by blocking the fast sodium channels in the nerve synapses regulating the heartbeat. One of the treatments is sodium bicarbonate. Better known as "baking soda", it also happens to be one of the most common substances used to cut pure cocaine, increasing the profits of drug dealers, without damaging the life of its users- another aspect of the "kill or cure" theme of sodium.

In London at five o'clock on a February evening, it is dark. So, when John came walking up the pavement toward 221b, it took him a moment to register that the front door next to Speedy's had just opened, and a person had emerged.

Given that the orange street light was four doors down from the flat, it was too dark on the doorstep to really see who it was, but John instantly knew it wasn't Sherlock. The person was wearing glasses, too short, and not dressed right. As an expelled breath frosted in the cold night air, the man pulled up the hood of a dark anorak over his head and headed away past the café, walking fast.  _Client?_

But, before the man left the step, John also spotted the guy stuffing a small plastic bag in his pocket, before he jammed his cold hands into the jacket. There was something about him that just screamed  _drug user_.

Without thinking, John started running, but the kid must have heard him, because he bolted off like a startled rabbit, ducking and diving around the pedestrians. John stepped off the pavement and into the street, which he knew would be clear of parked cars. Double yellow lines on Baker Street had been installed to stop parking and the threat of a car bomb, after Moriarty's little surprise package across the street. And since Sherlock's return, it helped keep the paparazzi at a distance, too.

Even so, the zig-zagging figure was widening the gap between them, and John was starting to run out of breath.  _I'm out of practice._  After more than two years of sedentary life, John realised he wasn't going to catch him.

The dealer might be faster, but John had the advantage of home territory. When the runner reached the cross roads and turned left, the doctor had already left the street and charged down the alleyway between two buildings. Cutting off the corner meant that he was ready and waiting when the hooded figure ran past the entry on the side street. In one swift movement, John snagged the guy's hood, grabbed his arm and spun him into the darkness of the alley. A quick kick to the knee put the figure down on the ground, knocking his glasses off. With one of his own knees on the dealer's back, and one hand twisting the guy's arm up his back, he snapped, "Just hold still."

"What the fuck are you doing, man?" It wasn't shouted, but the tone was both scared and angry at the same time, as John fumbled in the pocket, and withdrew the small plastic ziplock bag, with a white powder in it.

" _Oi_ , that's  _mine._  Get your own stuff."

Watson pushed the baggie into his own jacket pocket and wrestled the slim figure to his feet, shoving his face into the rough brick wall.

He was almost panting from the exertion, but John was also livid. Adrenaline from the chase collided with anger about what he'd just discovered: a person carrying drugs coming out of 221b. Given what Sherlock had just been through at Hartswood Manor, this was  _so not good._

"What were you doing with Sherlock Holmes?" This was growled in the most menacing tone he could muster between his panting breaths.

"Lemme go, you bastard. I ain't done nothing to get you so pissed."

"Oh, no? Then why aren't you shouting for help then? Because this is a class A drug I just found on you." He was feeling the other side of the guy's jacket, and realised that there was more where the first one had come from. "And you've got enough in this pocket to qualify as a dealer."

"You a cop?"

"Nope, but I know quite a few of them. I'm a doctor…and a concerned citizen, who knows what this stuff can do to you and the people you sell it to."

"Leave off, you're busting my arm."

John shoved the dealer harder against the wall, and then spun him around so he could take a good look at him.

Through clenched teeth, John asked the question that had made him run in the first place, "What were you doing there? Is Sherlock a  _customer_  of yours?"

Now able to see the dealer, John realised he was younger than he'd thought. And the kid looked scared.

" _Who are you_?" the youth whispered. "And what the hell business is it of yours what he does?"

"I'm Watson,  _Doctor_  Watson- and I want to know if you were selling drugs to Sherlock Holmes. Tell me, and I just might let you go." John let go of his hold, and stepped back, but the young man was kept pinned to the wall by just the anger in his tone.

The youth bent down to pick up his glasses and shoved them back on his face. "I was…getting my stuff checked." He shook his jacket back around his shoulders.

"Checked? What does that mean?"

John didn't get an answer, so he reached for the guy's arm again, but caught the sleeve rather than the flesh- the dealer wiggled out of his coat and was back out onto the side street before John could drop the jacket. He took a few strides after and then realised that there was no way he'd catch him a second time.

John slung the anorak over his shoulder, marching down the alley on his way back to the flat. By the time he got to the top of the seventeen steps, he was seething.

"What do you think you're doing?" John heard the harsh tone of accusation in his words, but couldn't restrain himself. The idea that Sherlock was using drugs again, so soon after returning from Hartswood was just enough to send John into his own kind of meltdown. He'd spent too many years in the army to ignore what drugs did to people, and too many years worrying about Sherlock's own danger nights to be anything but zero-tolerant. It had been an unspoken rule when he was living at the flat- not only no drugs, but no dealers or users either. Now that Sherlock was living on his own, clearly those rules were no longer being upheld.  _Where are Mycroft's eyes when you need them?_  How had the elder Holmes managed to miss spotting this?

John was standing in the doorway to the kitchen. Sherlock had not moved from his position sitting at the kitchen table, with his back to the door. The table could hardly be seen for the glassware- beakers, test tubes in racks. The rest of the space was taken by plastic bottles of liquids and boxed packets of chemicals that John had no idea what were. In front of Sherlock was a rack with one test tube, and a couple of small beakers.

"What does it look like I am doing, John?" It was said quietly.

The doctor watched Sherlock take a pipette, draw a liquid out of the test tube and stick it into each of the two beakers that had clear liquids in them. The first one instantly frothed into bubbles. Sherlock made a note in his small black book, and then stoppered the test tube, which had a sticky label and his spidery handwriting on it. He reached for a packet of paper strips, pulled one out and dipped it into the second beaker. It turned bright blue. He lifted it to the light and examined it carefully.

John came around the table, and looked into his friend's eyes.  _No pupil dilation._  Had he looked up at the bright fluorescent strip light in order to constrict them, so John wouldn't notice? He wouldn't put it past the man.

Sherlock ignored his scrutiny and put the blue strip down, lining it up with a sample sheet that had at least a dozen squares of blue- he was clearly matching intensity for some reason that John couldn't fathom. He decided that Sherlock was playing this very coolly for someone who had just managed to get over a nasty session of withdrawal only three weeks ago.

"Care to explain this?" He held up the ziplock bag of white powder.

Sherlock's brow furrowed. "Where did you get that?"

"Off your latest little visitor." He tossed it onto the table. "Were you buying or selling?"

Sherlock sat back in the chair and crossed his arms, looking offended. "Neither…and you're an idiot."

"I'm not the one using drugs, Sherlock." He pointed to the anorak, slung over the doorknob into the kitchen. "But he is- and he's not only using but selling. Well, at least I've got his supply here, which is headed down the drain as fast as I get the dirty dishes out of the sink."

Sherlock rolled his eyes. "Then you are even worse than an idiot. Now Spex is going to run the risk of buying bad stuff again, thanks to your little neighbourhood watch exercise. You should not have interfered; you've put his and others' lives at risk."

"What are you talking about?"

Sherlock gestured at the equipment. "I'm creating a testing kit, to try to protect people."

"People? You mean drug dealers?"

He got an outraged glare from Sherlock. "Drug dealers  _are_  people. John. The people they sell to are people, just like you or I."

John responded with an equally icy stare. "You know what I meant. Of course, they're people, but they're not people you need to be around. If you are aiding and abetting criminals, you are running serious risks, Sherlock. And exposing yourself to their company is  _so_   _not good_  at the moment- if it ever was."

"You have no idea what you are talking about. Before you start accusing me of something, for just a moment, have the decency to  _listen_."

John was taken aback by the icy tone in Sherlock's voice. It wasn't defensive; it wasn't the anger of someone who had been found out. It was pure steel- and it was new, something that John had not heard directed at himself by Sherlock ever before.

John pulled out the kitchen chair on the other side of the glassware jungle, sat down, and crossed his arms, saying quietly, "Okay, I'm listening."

A pair of grey green eyes fixed on his. "Good." Sherlock was not smiling. Whereas before his disappearance he might have shouted and been almost child-like in his temper, now Sherlock had a great deal more self-control.

"Have you ever heard of levamisole?"

John shook his head. "What is it- a new legal high?"

"No. Levamisole is a licensed drug that was developed in Belgium in 1966. It was designed to be an anthelmintic, used to help people and animals expel parasitic worms. Because it supresses the immune response it was used in some cancer treatments. However, fifteen years ago, it was banned in the USA for any use in humans. You can still buy it for use in fish tanks and for farms; vets use it, too."

"What does this have to do with illegal drugs, Sherlock?"

"In the past, the Latin American based producers of cocaine shipped nearly pure product- and let the dealers cut it with their own inert filler. In the good old days, most used sodium bicarbonate- common baking soda- you can buy it anywhere and it has no adverse effect at all on users, except to dilute their high. However, a decade ago, some bright chemist tried mixing cocaine with levamisole- and found that the two interact to give an enhanced high. So, adulteration of cocaine with the cheap stuff actually made the high better. Even better was the fact that the cocaine manufacturers could get their hands on this stuff really easily, as their economies were awash with legal supplies for the animal sector. So, they started doing it themselves, at the point of manufacturing."

"So, mixing two bad drugs together to make more profits, why is this important?"

"Because the reason why levamisole was banned was because of the adverse effects it had on humans- including necrotic vasculitis. Over the past three years, cases in London of people suffering from the side effects of levamisole have escalated dramatically. If you worked in an Emergency Department instead of general practice, you'd have seen the epidemic first hand. Livid black purple patches on a victim's face, hands and legs- it isn't pretty. And the necrosis is not the worst of it; it also causes neutropenia, reducing a person's white blood cells, making them more susceptible to infections. They  _die_ , John."

He gestured to the anorak that John had hooked onto the door knob. "I've been trying to educate dealers, because if they can be taught to buy cocaine only from the wholesalers who don't use levamisole, then there will be fewer people dying. The word is being spread as well to users who are buying cocaine- they've got to find suppliers who can prove the quality of their materials."

"How can you be doing this? You, an addict?  _Working_  with drug dealers? Do you get paid in kind for your services?" He couldn't keep the dismay out of his voice.

"This isn't about me, John. I can save lives if people learn to stop consuming levamisole; it's lethal."

"So is cocaine."

Sherlock rolled his eyes. "If that were true, John, then the use of cocaine wouldn't have quadrupled in the UK over the past ten years. Most people don't use it even once a month, so don't get into difficulties with the drug. Two point four percent of the entire UK adult population has used cocaine at least once over the past year."

"Including you."

This provoked Sherlock, who pushed back in his chair and crossed his arms. His demeanour stiffened. "Why are you so…intolerant?"

"Cocaine is an epidemic, Sherlock. It's now so cheap that anyone can get a hold of it. It's  _addictive_."

"Not in the same way as heroin."

John's eyes narrowed and his jaw tightened. "And you would know, from personal experience with both drugs. Jesus, Sherlock, I can't believe we are having this conversation. You've just gone through hell to get clean. You don't need me to remind you that you are seven times more likely to die of a heart attack before you're forty because you've used cocaine. You might not give a toss about your own life, but others do- me included. No, let me rephrase that- me  _especially_. Cocaine doesn't just hurt the user; it ruins other people's lives, too. How many more times are you going to make me say this? If you don't stay away from drugs…" He ground to a halt, trying to get his temper under control.

Sherlock sighed. He uncrossed his arms, rolled up his sleeves and lifted his elbows to show the underside of them to John. He hissed, "I'm  _clean!"_

The silence deepened as the two men glared at each other.

Sherlock broke the deadlock first. "I'm  _not_  using. And the presence of a particular chemical in this flat does not make me any more or less likely to use than if there wasn't any cocaine here." He waved his hand at the jacket. "I make them take whatever they have on them away, once they give me a testing sample, and I give them their own testing kit. And it's also the reason why I run the sample immediately- so I can dispose of the excess." He took a deep breath, then pointed at the rack of test tubes. "That's Spex's sample. Not even enough for a single dose. Just enough to run a chemical analysis on, so I can tell him what's been used to cut it, and whether it's safe."

He slapped his hand down on the kitchen table, making the test tubes rattle. "This isn't about me, John. It's about others. You should understand that motivation better than most people. You're the one who spent two tours of duty in Afghanistan, trying to save people's lives. It's a bit rich now for you to be criticising me for trying to do the same."

That stung. Defensively, John muttered, "comparing serving soldiers to cocaine users is just not the same, Sherlock."

"No? Then explain it to me. At least a soldier goes into battle knowing he is risking his life. A person who uses adulterated cocaine doesn't know it's going to kill him. Only one in ten users develop this kind of reaction- but it can happen on one dose or hundreds. There's no way of knowing. It's like playing Russian roulette."

"There's an answer to that." John couldn't resist interrupting. "Don't take cocaine."

Sherlock just shook his head. "This problem isn't so simple. Levamisole hurts the people  _least_  able to protect themselves- the poorer users, the homeless, the unemployed. If you're wealthy, you can afford the purity. If you're not, then you buy cheap. The £40 wrap of coke they consume may only be 10% cocaine, and the rest fillers. When sodium bicarbonate, sugar, or caffeine are used, the impurity doesn't kill you. It's the people on benefits, those on the streets, the less well educated users who are getting the lethal rubbish."

"The kid who was here- you were testing his stuff? Is he part of your homeless network?"

Sherlock rolled his eyes. "You make that sound like they are paid employees of mine, John. I'm not Mycroft; I don't have  _staff_.I just let it be known that I can help protect people from bad stuff. I've only seen Spex twice before- on non-drug related things, so you can relax."

"I don't know how to relax when it comes to you and drugs, Sherlock."

Sherlock grimaced. "Then I would ask you to trust me, but you don't seem able to on this issue, so… I can prove that Spex was here to get a testing kit. Check the jacket's left pocket; there's a tin in there- looks like it's for roll-ups."

John fished out a well battered old tin from the anorak and opened it. There were three vials of clear liquid, one with a blue top and the other in red; the third top was white. There was an eye dropper, a pile of paper slips in a rubber band and a rolled up piece of paper. He unfurled the scroll and saw that it was a shorter version of the chart of colours that Sherlock had consulted when John first arrived.

"It's a basic PH test. The bluer the colour, the more likely it is that it is cut with baking soda. First tip some of the powder someone is trying to sell you into the white bottle and shake. Take an eye dropper measure of that and put into the red vial- that's got hydrochloric acid in it. If it's sodium bicarbonate, it should bubble- that's pretty conclusive. If it doesn't bubble, then take another eyedropper full and put it into the blue topped vial. Dip one of the slips in it. If it comes out pink, they shouldn't buy- that's most likely levamisole."

He sighed. "Of course, that's only part of the problem. I'm working on a colour match test for the other fillers that people need to be wary of- dental anaesthetic, over-the-counter painkillers, ketamine. That's why my price for a test kit is a sample. If I can help users understand the risks- that cheap means bad- and to test before use, then the numbers of deaths will fall."

John looked down at the kit. "I don't know, Sherlock. You're  _enabling_  drug dealers. You are letting them come here with their product." He looked up from the kit. "When I think of cocaine, all I can think of is the time you told me that you overdosed. You've tried to use cocaine to kill yourself before I knew you- you told me. And having this stuff anywhere near you now? It  _scares_  me."

Sherlock waved a hand in dismissal. "You're a doctor. You dispense drugs all the time. Legal or illegal- they're all chemicals. Some of them can kill people, if the dosage is wrong. Doctors- qualified medical professionals who should know better- have been injecting me with drugs since before I could walk. I wasn't given a choice. They didn't know how the drugs would work in  _my_ case- they just assumed that my biochemistry is normal. It isn't, as you know. They've given me several different drugs that shouldn't interact badly, only to find that they do for me. I was always just told –'Take your medicine; be a good boy'. Nobody ever asked me for my opinion about the chemicals they were forcing into me."

Sherlock gestured to the table of glassware in front of him. "When I chose to take drugs, at least I knew what effect they have. I could control the quantity and verify the quality. I am a  _chemist_ , John. That means I know what I am doing."

John heard the shift from past to present tense and tried not to cringe at the implications. For a split second, he really tried to understand it, tried to put himself in Sherlock's position. But, he couldn't help himself. "Then you  _know_  that cocaine increases impulsiveness and risk taking. It warps judgment-  _you used it to try to kill yourself_ before I knew you!" He did nothing to disguise his anger.

John looked away into the living room, drew a ragged breath and pinched the bridge of his nose. When he had calmed down, he looked up. "Sherlock, I must have asked myself a hundred times in the days after Barts whether you were high at the time on the roof. You weren't making any sense, what you said on the phone. I thought you had relapsed, and I hadn't seen it, wasn't able to stop you…" He made no apology for the pain that made his voice break; the memory of Sherlock's suicidal leap off the roof was not something he could forget. Ever.

Sherlock looked down at the table, suddenly still. "I'm sorry. I've said so. Repeatedly. I … had no idea that it would distress you so."

"Well, it did, and it still does, even now, when I know what made you decide to jump and all that followed. But, that's why I'm more than just a little… intolerant."

The silence drew out. Finally, Sherlock shrugged. "Well, in terms of my overdoses, cocaine wasn't the worst; that accolade was reserved for tricyclic antidepressants- and that was administered by a medical professional."

John frowned. "I don't remember seeing that in your medical files." He'd been given the pile of records to go through four years ago, at Mycroft's insistence.  _You need to know what you're dealing with, Doctor Watson._

Sherlock sniffed. "No, my brother would have taken steps to make sure that didn't get into the public domain. It doesn't matter. It was …long ago and far away. What matters now is right here in front of us. I am able to make a difference here, with people who need help. I can't believe that you would want me to let people die unnecessarily. You are the one who said  _caring_  matters."

John felt caught on the horns of the dilemma. He wanted…no,  _needed_  to trust Sherlock, for both their sakes. But he also wanted to reduce the temptation. He remembered what Sherlock had said about taking the overdose two months after re-hab. It was only six weeks since Hartswood. As much as he respected Sherlock's need for autonomy, this was one choice he would not, could not allow him to make- or even to consider. He'd said as much to Sherlock before leaving Reigate- losing Sherlock again would destroy John. And the presence of that white powder in the flat made it all too  _possible_.

That's when the solution came to him.

Putting both hands flat on the table, he looked across the kitchen at his friend. "I'm going to propose a practical compromise, Sherlock. Write up the specs of your testing kit, and make that one you gave Spex into a prototype with a user's manual. I'll call in a few favours with some people I know in the NHS Live well programme, and the Release and Addaction networks. If we can get your testing kits made up properly and distributed along with the needle syringe programmes, then it could make a difference- start educating people. I'll get them to collect samples handed in and the Forensic services can do the tests to give you the colour match data to finish your colour chart. But, you need to promise me that as of tonight you will stop doing the collection and testing yourself. No more drugs in Baker Street."

Sherlock sighed, his brow furrowing as he looked down at the equipment.

John decided to lay his cards on the table. "Please…This isn't about you. It's about  _me._ "

Finally, Sherlock looked back up to John, and then nodded.

John gave a mental sigh of relief, as he breathed out a "thank you."

oOo

"Mister Ranger; it's Forton here. I'm sorry to be ringing you at this hour, but there's a situation at the Priory that needs your immediate attention."

A quick glance at the alarm clock on the bedside table confirmed what Philip Ranger thought- it was just after midnight. As CEO of Research Associates, one of London's best and most discreet private investigation firms, he had earned his right to an unbroken night's sleep. He rarely got involved in any particular client's work; he was now concerned with the management of an international business with over four hundred employees.

However, there were exceptions, and this was one of them. As a result, he went from half asleep to wide awake before Forton had finished speaking. This was a 'particular' client and he did not like the idea of an 'incident'. All being well, the patient in question was supposed to be going home in less than a week.

His tongue woke up a few seconds later and he barked out, "What's happened?"

"I've been listening as instructed, sir, ever since the bug was planted. The patient doesn't sleep much, but there's not been anything odd over the past weeks until tonight. I'll let you listen to the recording just to be sure I'm not over-reacting, but I think he's just been drugged by one of the staff, not medically authorised. Wish to hell that we'd managed to get a video feed in there, but the audio suggests it."

Ranger's heart rate leapt. The idea of explaining to the particular client why his younger brother had been mistreated whilst supposedly in the care of one of north London's most expensive private hospitals did not bear thinking about. His throat suddenly went dry. Ranger rasped, "Play it  _now_."

There was the sound of a recorder button being pushed, then a brief hiss before the distinctive sound of an electronic door lock being released.

"You awright?" The Yorkshire accent was distinctive and friendly.

"You aren't on nights, at least not on this floor. Lost your way?"

Ranger recognised the public school vowels of the seventeen year old his firm had been asked to keep watch over.

The caustic comment from the patient provoked a laugh. "You in charge of my rota now?"

There was no reply. The sound of footsteps got louder as the nurse approached the bedside table where the microphone was hidden.

"Here's fresh water and your meds. Knock 'em back."

"Anything to get rid of you."

A pause, then the nurse again. "That wasn't so horrible, was it?"

"Leave. Now, before your presence contaminates my thought processes even more than you already have the air."

"Charming". The man's footsteps went away, and the door lock sounded again.

Forton interrupted. "Nothing happened out of the ordinary- he did his usual thing of going to the loo to brush his teeth after the bed check, had a drink of water and then went to bed."

Ranger heard the tape being fast forwarded. "An hour and ten minutes after he left, the nurse comes back."

The CEO closed his eyes and tried to image the scene. The door lock clicked again, and footsteps came closer to the mic.

There was a chuckle. "That's shut you up, didn't it just."

There was no reply.

"Wakey, wakey. This'll be more fun if there are two of us playing."

A sound of cloth being moved; Ranger guessed it was probably the bedclothes.

"Let's take a proper look at you, pretty boy."

A sleepy baritone eventually slurred, "wha're you doing?"

It sounded odd after the crisply popped consonants of the boy's earlier recorded comments.

A chuckle from the nurse. "That's more like it. Taken the edge of all that toffee-nosed arrogance."

"Wha've you done?"

"Given you something to relax you."

"Noooo….the pills…I threw them up."

"Aye, but you didn't think to check the water, now did you? You always have another glass of water before you go to sleep- I've figured that out from the levels in the jug. Which reminds me…time to get rid of the evidence." The sound of footsteps walking away, and water splashing. Ranger could visualise the contents of the jug and glass being put down the sink. The tap was turned on full. A few moments later, and the nurse was back.

"Yuk- that wasn't pretty. Hiding your vomit by putting it down the drain instead of flushing it- smart kid. Well, not for much longer."

"Drug …in the water?"

"Yep. Flunitrazepam…just enough to make you open to a little suggestion."

"Soooo-jest-shun." The boy drew out the vowel rolling it around as if playing with the word. "Jest? Is it funny?"

This time it was the nurse who didn't answer.

There was a soft giggle. "Is my glass part of the joke?" There was a child-like curiosity in the question.

"Fingerprints, pet…needed for the nice evidence trail."

"A…trail... to what?"

The nurse chuckled. "They're going to be left in the medicine cupboard- your means to escape this place. So, less a what, more a why.

This provoked another giggle from the boy, who was clearly feeling the effects of the drug. "who's next."

"What?" The Yorkshireman was now the one who was a little confused.

"You're a bit thick."

"No need to be rude, posh boy."

"Leggo… wanna sleep." The speech was even more slurred and drowsy.

Now the sounds became harder for Philip Ranger to decipher. Rustling, probably the bed clothes again- but it didn't sound like a struggle. A chuckle, "ooh, lights out then? Good, you being asleep's going to make the rest of this simple."

Then the sound of something different. Plastic? He tried to think of what it might be. Why would someone drug the Holmes boy? And what was the nurse doing to him now? Was it to get him into trouble, screw up his exit plans? But, even if the drug he'd just unwittingly ingested made his memory hazy, surely he'd be able to remember the nurse and what had happened?

"Geeze, your skin's like a bleed'n road-map. This is going to be a dawdle."

There was a sound like a snap of elastic that puzzled Ranger. Odd random sounds followed. Eventually, there was a strange sort of clink, as if something had fallen on the tiled floor. Then footsteps, heading away from the bed toward the door, and the sound of the electronic door release.

Ranger would visualise the Yorkshireman turning at the door to look back at the now sleeping boy in the bed.

"And it's Goodbye from him, and Goodbye from me." Then the door shut.

Forton came back on the line. "That's all, sir; it's been quiet since."

Philip Ranger tried to understand why the nurse would say something that was used by the Two Ronnies, comedians who used to end their show with that strap-line.  _Wait a minute…_  wasn't it "goodnight from him and from me"? Why make it "goodbye"?

The pieces suddenly slotted together.

" _WHEN? HOW LONG AGO DID THIS HAPPEN_?" he shouted down the line.

"About fifteen minutes ago, sir; I called you as soon as I checked the recording."

"Right, do exactly as I say and do it fast. Dial 999 and say you are calling from the Priory. Get an ambulance over there as fast as you can- it's a matter of life or death. That nurse just gave Holmes a lethal injection, but he's making it look like a suicide." There was a sudden intake of breath. "Get over there  _now!"_ Ranger knew that Forton was listening in from his home in Southgate- he'd been the one they'd got to plant the bug in the first place. "Keep me informed; you'll have to call me and tell me which Emergency Room they're taking him to- could be the Whittington, Barnet or the Royal Free. I'll get onto his brother. And, Forton-  _HURRY!"_

Less than a minute later, Ranger was listening to Mycroft's voice mail. "The number you have rung is currently not in service. Please leave a message." The recorded voice was an anonymous woman, with an untraceable accent.

"Call me. Your brother's been attacked."  _No time for details._

When Ranger tried Mycroft's home phone, the housekeeper answered.

"I'm sorry, Mister Ranger, but he's away overseas. I am not sure how to get a message to him."

 _Of course._ If someone was going to attack his brother, they'd do it when the man's away from home.

He made a call to a number that he'd been given, "to be used only in the case of dire emergencies, when I am not picking up my mobile or the home landline." Ranger had an inkling what his illustrious client did for a living, but had been sensible enough not to provoke a lie.  _Don't ask, unless you need to know._  His professional career was based on keeping client information confidential- and having the sense not to need superfluous information.

"Hello?" It was an anonymous male voice, British, instantly forgettable.

"I need to get an urgent message to Mycroft Holmes. This is Philip Ranger. His brother has been attacked and taken to hospital for a medical emergency. Get him to call me as soon as possible."

There was a pause, then a quiet, "I'll see what I can do." And then the line went dead.

Seventy three minutes later, Philip was in the Barnet Hospital, the closest Emergency Department to the Priory because the ambulance crew had only minutes to get him to a trauma resuscitation unit. He'd met Forton outside the room, pacing.

"Report." If Ranger tended to snap back into military mode when he was under stress, it was understandable- he'd been in Special Operations- as had many of his staff.

"I got there minutes after the ambulance crew arrived- they were still in the reception arguing with the Priory Staff, trying to talk them into checking Holmes' room. The staff thought it might be a prank call; the night doc was arguing that he hadn't authorised any call-out. I told them I made the call, and that the boy was unconscious- which he was by the time we got up there. And he wasn't breathing."

"Shit."  _Please don't make me have to tell Holmes that the boy is dead._ "…Go on."

Forton then recounted how the crew had used a mask and a bag to force respiration and loaded the patient into the ambulance. He'd followed in his car behind. "By the time I got here, the kid was in there, being worked on. They're still at it, so I suppose that's good news- but the staff won't tell me a thing, because I'm not family."

"What did the Priory say?"

"They think it's a suicide attempt, sir- a deliberate overdose, because they found the vials on the bedside table and the needle on the floor. They didn't call the police- said they had to wait until they contacted the parents. I didn't tell them that there aren't any, and I didn't say anything about the bug, or the nurse- just said the boy called me; told them I was a friend."

Ranger took an executive decision. "Right, I want you to go back to the Priory now. Find out who that nurse is. If he's still there, great- but I suspect he's buggered off, duty done. Your job is to find him and get him into our custody. No police- not yet, anyway- that's up to the client. Just make sure the chain of evidence is kept clean."

As Forton vanished into the night, Ranger wondered how long it would be before Mycroft Holmes would show up.  _Please let the boy still be alive when he gets here._  He made another call to that number.

"Hello, Mister Ranger." It was the same voice.

"Have you reached him?"

The man on the other end did not reply, but asked his own question. "Have you an update? I may be able to pass it on."

"Tell him to get to Barnet Hospital- and hurry, before it is too late."

Three hours later, Ranger was just finishing his second coffee. The boy had been moved from the trauma resus room, admitted straight into ITU. All the doctors would tell him is that they needed a next of kin, soon. He told them that the family member had been informed and was on his way. Ranger stayed downstairs in the Emergency Department- when Mycroft showed up, it was likely to be there first, given the relayed message. And he needed to deliver this update in person.

While waiting in the uncomfortable plastic chair, Ranger rehearsed the case. He'd often wondered about the young man's obsession with his brother's whereabouts. Research Associates had done its homework before taking him on as a client. The Viscount was not forthcoming about his Government job, but the missing person brief was clear. So, it seemed straightforward. Most sixteen year olds who take a hike are easy to find, but both of the Holmes brothers seemed quite challenging in their own ways. As the weeks of searching turned into months, Ranger had watched the pressure building on the older brother. When the blackmail envelopes showed up, Ranger realised that there was more to this than the normal missing kid scenario. He watched his client's anxieties building to the point where he wondered when rather than if the young man would break down. On the day when the police photo search had triggered one of Ranger's police informants to make the call, he thought that the case was solved, and he celebrated that night, thinking it was a job well done- the kid had been found and was now safe in rehab- another satisfied client.

The call from Mycroft Holmes three weeks later told a different tale- the Viscount's worries were not over. Despite Holmes' insistence, he'd taken some persuading to plant the surveillance device- it was not legal, and if the kid had not been designated a vulnerable minor, Ranger might have said no. But, in the circumstances, he thought no jury would ever prosecute a legal guardian for taking what might have seemed excessive care. After all, the boy had a record of mental health instability and drug abuse, and was a flight risk. And as the legal guardian was being blackmailed about his brother, should it ever come to a trial, he would have a sufficient case for taking such actions to keep his brother safe. So, he'd gone along with it, and got his people to plant the bug and bribe the nurse to get daily reports.

And now he knew why.

At a quarter to five in the morning, Mycroft Holmes arrived in the Emergency Department. Despite the early hour, the waiting room was nearly half full, so Ranger had time to look at the young man before he spotted him. Holmes had obviously travelled hard- clearly exhausted, unshaven and wearing clothes he'd been in too long.  _He looks shattered_.

Ranger gave him a reassuring smile even before they came together. "He's still alive."

The relief was plain in the tired blue eyes that looked at him. "What happened?"

"Someone drugged him with a lethal dose, and made it look like a suicide attempt. The ambulance got him here into resus, and then he was admitted to the Intensive Therapy Unit. It's upstairs- third floor. I'll take you there."

"Do you know who did this?"

Ranger nodded. "We're working on it. My man has tracked down the nurse who administered the drug- we've got it on tape. He found him at his home, with tickets for a flight to Brazil, leaving later this morning. I haven't contacted the police – not yet, anyway."

Holmes' look hardened. "He's going to miss that flight. I do hope you have put this person in a safe place. I will need to have a word with him."

"I thought you might; he's secure where you and I can question him, after you've talked to the doctors here. They won't give me any details, because I'm not family."

The ITU at Barnet Hospital was reasonably sized- 23 beds split into two wards, with a central administration unit between them. Even at just after five in the morning, there was a sense of urgency and activity.

"I'm Mycroft Holmes. My brother has just been admitted."

The nurse did not have to look at the screen; she nodded. "Yes, he was brought up three…uh, actually four hours ago. Sorry, it's been a long night."

He didn't smile. "I need to see him and the consultant who is treating him."

She raised an eyebrow. She pointed to the ward on the left side. "In there. The doors are controlled; I'll buzz you in. The  _doctor_  on duty tonight will be with you shortly; consultants won't be in until the next shift."

When he got to the door, he heard the electronic lock release. It made him think. The people who Ford had hired to do this to Sherlock would find out that he had survived, and they might try again. Mycroft was momentarily glad for the additional level of security. But then he sighed.  _Stupid._  It had been a medical professional that had drugged Sherlock- and they might well be able to slip through this hospital's procedures just as easily as they had circumvented the Priory. He would have to take special measures.

The third bed he glanced at was occupied by Sherlock. Standing at the foot of the bed, for a moment, all Mycroft could focus on was the electrodes and wires, the tubes and the machines clustering around the bed, obscuring his brother. The electric hum of equipment, the glowing digital displays and flashing monitor lights competed with the muffled thump and wheeze of a ventilator. The tube that was down Sherlock's throat was an obscene intrusion. Mycroft took in the various bags held on a pole, tubes running into one thin arm, and another tube running out from under the covers to another bag hanging on the side of the bed.

Under all that paraphernalia lay his brother, his dark hair lying in stark curls across the white sheets. What skin he could see looked pale. For a moment, Mycroft was drawn back to an earlier memory- the last time he'd seen his mother in hospital, dying of pancreatic cancer. He'd stood at the end of her bed and wondered, s _he's alive now, but for how much longer?_ The same anxiety now seized his chest and squeezed- only harder.  _This is my fault. He's my responsibility_.

The sound of a soft sole on the lino floor behind him announced the arrival of a medical professional, but Mycroft didn't lift his gaze from Sherlock, using the moment to try to get his face back under control, to wipe the horror off his countenance.

"You're the patient's brother?"

Mycroft noted that the woman's accent had remnants of South Asian inflection, overlaid with an East End cadence. Probably first generation.

"And legal guardian." He turned to look at a female in a white coat who was far too young to be looking after his brother. "Who are you?"

"Doctor Sarkar." She was short and had a round smiling face. West Bengali, Mycroft thought. Unmarried, professional.  _And probably the pride of her family._

She didn't look to be much older than he was. How can someone that young be able to protect his brother?  _I can't do it; you won't be able to, either_. "You look too young to be a doctor."

That comment irked her. "You're not the first to say that to me, Mister Holmes." With a rather annoyed sigh, she added, "…and you won't be the last. You  _asked_  to speak to me."

He looked back at the still figure on the bed. "I need to know  _exactly_  what happened to him and what the prognosis is."

"There's a short answer to both. He took a lethal overdose, and he may survive it, or he may not."

That made him cross. "More details, please,  _Doctor._ "

"Right," she snapped out of under her arm the clipboard she was carrying. "The ambulance was called to the Priory Hospital just after midnight. The crew found the patient unconscious. Evidence was seen that he'd injected 20mls of amitriptyline, a tricyclic antidepressant medication. The patient was showing signs of apnea, with possible respiratory arrest. They used manual ventilation- a mask and squeezed bag- in the hope of raising his blood oxygen levels, which were below 83%. In the rig on the way here, the patient suffered a seizure of three minutes duration." Annoyance was driving her delivery, sparing him nothing and not stopping to explain much of the medical jargon.

She lifted another sheet of paper on the clipboard. "Upon arrival here at the Emergency Department, he was intubated to protect his airway. Three milligrams of physostigmine salicylate was injected to try to reverse the effects of the amitriptyline poisoning. An ECG was taken, revealing sinus tachycardia of 125bpm, a dominate R-Wave in AVR, and a QRS duration of over 100msec. One hundred millimoles of sodium bicarbonate were administered in the hope of re-opening the sodium channels in the nerves controlling the cardiac system. Nevertheless, a few minutes after the sodium bicarbonate, he went into VF and had to be shocked- repeatedly. The third shock restored some semblance of a proper heartbeat, although rather tachycardic. Then seven minutes later he had a second convulsion. Diazepam was administered as an anticonvulsant. It took a further thirty minutes before the patient was more or less stable for a period of ten minutes, after which he was admitted and brought up here."

She kept on, each word ratcheting his anxiety tighter. "And once here, he was put on a proper ventilator, as you can see. We are monitoring his symptoms, trying to control his temperature in particular." She gestured to one of the monitors. "It's one of the symptoms- hypothermia. The drug affects his ability to sweat, so he overheats. It depresses urinary output too and that slows metabolising the drug and its excretion. That can cause more seizures and yet more cardiac problems- both of which are side effects of the serotonin storm unleashed by the overdose. The drug won't be out of his system for another thirty six hours, and even then the side-effects will last for days."

Mycroft willed his tongue into action, and took some pride in the fact that his voice sounded calm and measured as he asked "What happens next? How long will it take for him to recover consciousness?"

Doctor Sarkar shook her head. "He may never do so. You need to understand how serious this is. Most TCA overdose cases never even make it to the hospital. Nearly three hundred people a year die from this every year in England. A lot are killed by MIs- that's myocardial infarctions… heart attacks. Quite a few end up in deep comas, and then die. Your brother is currently in a coma."

The anxiety squeezing his chest tightened its grip, like a boa constrictor. He tried to take in the medical terminology. The words that stuck out were shocking- seizures, heart attack, coma. He put up barriers, little  _no go_  areas around them; there would be time later to think through what those words meant in the context of a seventeen year old boy.

In a matter-of-fact tone, the young woman continued, "Even if he wakes up, the recovery is complicated- confusion, agitation and hallucinations are common. And, given that we have no idea when he took the drugs, and therefore how long he was deprived of oxygen, there may well be brain damage."

She paused for breath and gave him a rather pained smile. "Let's assume a best case scenario- that he survives the next 36 hours, he does wake up, that his cognitive functions are unimpaired and that the recovery period is quick. There is always the fact that this was a suicide attempt. The tox screen showed levels of amitriptyline in his blood that were  _twice_  the lethal dose. What he's tried tonight, if he survives it…he may well try again."

 _But it wasn't self-inflicted._ Mycroft nearly blurted that out, but managed, just, to stifle his contradiction in time. He couldn't tell here that this was not suicide, but rather, a murder attempt. Not until he'd had a chance to see if he could link it back to the real killer.

He looked back down at his brother lying there on the bed, allowing the doctor to think that he was trying to deal with the fact that it was a suicide attempt that had put Sherlock there. That bought him a few moments to force his tired mind to focus.

Ford must have become tired of waiting, or decided to strike because he knew that Mycroft was away in the Balkans assessing the strength of some intelligence networks newly re-established in Bosnia. The Dayton Agreement was only six months old, and the eighty thousand men in NATO's IFOR were trying to ensure that the peace held. Mycroft had been sent in to explore whether the CIA's claims were true- that Hizbollah and Iranian Revolutionary Army support was still actively supporting the Bosnian Muslims. The CIA trusted him, given his previous contacts with Langley over the Mexican business. They would believe him when he reported that they were seeing ghosts rather than a real threat. Mycroft figured that Ford must have been waiting for the opportunity of his being away, timing his attack on Sherlock to coincide with his absence.

 _Stupid._  He shook his head, not caring if the doctor saw it. He was being stupid. The mission he had been sent on had probably been engineered by Ford for just that purpose.

Suddenly, something in Mycroft gave way. Fear and anxiety were catalysed into anger- a deep smouldering rage that wanted to kill something…or someone. He knew he couldn't attack Ford directly. But now – just possibly- now he had a chance to gather some incriminating evidence. The man being held by Research Associates, the nurse who had given Sherlock the drugs, was the first tangible lead he'd got. And to make sure that he had the opportunity to do just that without police interference, he could say nothing to dissuade the doctor that Sherlock had tried to kill himself.

"I have urgent business that I must attend to, but I am now back in London, and reachable on a mobile number. I'll leave it at the reception. Please call me if his condition deteriorates further. I should be back later this afternoon or early evening."

She eyed him carefully, as if judging his cool demeanour.

He went to find Philip Ranger.  _There is work to be done._


End file.
